KR102624882B1 - Compound with ketal group, photocurable composition including the same, photocurble film formed from the photocurable compositon, and image display including the photocurable film - Google Patents

Abstract

The present invention relates to a novel ketal-based compound, a photocurable composition containing the same, and more specifically, to a ketal-based compound represented by a specific chemical formula, and a photocurable composition containing the ketal-based compound as a photoinitiator. As the photocurable composition includes the above-described ketal-based compound as a photoinitiator, the crosslinking reactivity and sensitivity of the photocurable composition may be excellent. In addition, it is possible to provide a photocurable film formed from the photocurable composition and having high hardness and degree of cross-linking, and an image display device including the same.

Description

Ketal-based compound, photocurable composition containing the same, and photocurable film and image display device formed therefrom

The present invention relates to a ketal-based compound, a photocurable composition containing the same, and a photocurable film formed therefrom. More specifically, it relates to a ketal-based compound containing a nitrogen atom, a photocurable composition containing the same, and a photocurable film formed therefrom.

A photoactive compound is a substance that initiates a photopolymerization reaction by being decomposed when irradiated with light to generate chemically active ions, atoms or molecules, such as radicals or acids. Photoactive compounds are generally used as photopolymerization initiators for compositions that are cured by irradiation of light, such as photocurable ink, photosensitive printing plate, photoresist, etc.

As examples of the photopolymerization initiator, benzophenone-based compounds, benzoin-based compounds, triazine-based compounds, biimidazole-based compounds, oxime ester-based compounds, phosphine oxide-based compounds, ketal-based compounds, and acetophenone-based compounds are mainly used. .

If the sensitivity of the photopolymerization initiator to light irradiated from the light source is low, the photopolymerization reactivity of the composition may be reduced, for example, the degree of crosslinking of the photocured product formed therefrom may be reduced, and hardness and durability may be deteriorated. In addition, the photopolymerization initiator must have high thermal stability and storage stability, making it easy to handle and store, and photocurable compositions containing the photopolymerization initiator are continuously required to have excellent stability over time and storage.

However, when a conventional radical photopolymerization initiator is used as a photopolymerization initiator of a photocurable composition, for example, a composition for a hard mask, sensitivity to light and photopolymerization reactivity during the curing process are low, and the curing rate of the surface and deep portion of the photocurable product is low. may decrease, resulting in deterioration of mechanical properties.

Therefore, in the curing process, there is a need for the development of a photopolymerization initiator with a new structure and a photocurable composition containing the same, which has excellent sensitivity, photopolymerization reactivity and stability, and has excellent curing degree on the surface and deep portion of the coating layer.

For example, Korean Patent Publication No. 10-2014-0099560 discloses a photocurable composition containing a photopolymerization initiator.

Korean Patent Publication No. 10-2014-0099560

One object of the present invention is to provide a ketal-based compound with excellent sensitivity to light and crosslinking reactivity.

One object of the present invention is to provide a photocurable composition having excellent photopolymerization reactivity, storage stability, and high crosslinking density.

One object of the present invention is to provide a photocurable film formed from the above-described photocurable composition and an image display device including the same.

Ketal-based compounds according to exemplary embodiments may include at least one of the compounds represented by Formula 1 and Formula 2 below.

[Formula 1]

In Formula 1, R ₁ and R ₂ may each independently be a hydrogen atom, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aliphatic hydrocarbon group with 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom.

In one embodiment, R ₁ and R ₂ may be connected to each other to form a ring.

X may be a halogen atom. For example, X may be F, Cl, Br or I, preferably F or Cl.

[Formula 2]

In Formula 2, R ₃ and R ₄ are each independently a hydrogen atom, an aliphatic hydrocarbon group with 2 to 10 carbon atoms, or an aliphatic hydrocarbon group with 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom,

R ₅ and R ₆ may each independently be a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom.

In one embodiment, R ₃ and R ₄ may be connected to each other to form a ring, and R ₅ and R ₆ may be connected to each other to form a ring.

According to exemplary embodiments, the compound represented by Formula 1 may include at least one of the compounds represented by Formulas 1-1 to 1-18 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Formula 1-6]

[Formula 1-7]

[Formula 1-8]

[Formula 1-9]

[Formula 1-10]

[Formula 1-11]

[Formula 1-12]

[Formula 1-13]

[Formula 1-14]

[Formula 1-15]

[Formula 1-16]

[Formula 1-17]

[Formula 1-18]

According to exemplary embodiments, the compound represented by Formula 2 may include at least one of the compounds represented by Formulas 2-1 to 2-8 below.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

[Formula 2-5]

[Formula 2-6]

[Formula 2-7]

[Formula 2-8]

Photoinitiators according to exemplary embodiments may include the ketal-based compound.

Photocurable compositions according to exemplary embodiments may include the photoinitiator.

In some embodiments, the photoinitiator is a benzophenone-based compound, a benzoin-based compound, a triazine-based compound, a biimidazole-based compound, a phosphine oxide-based compound, an oxime ester-based compound, an acetophenone-based compound, and a thioxanthone-based compound. , it may further include at least one of an anthracene-based compound and an anthraquinone-based compound.

According to exemplary embodiments, the photocurable composition may further include a photopolymerizable compound and a solvent.

In some embodiments, the photopolymerizable compound may include a (meth)acrylate-based compound.

In one embodiment, the content of the photoinitiator may be 0.1 to 5% by weight of the total weight of the photocurable composition. In one embodiment, the content of the photopolymerizable compound may be 10 to 90% by weight of the total weight of the photocurable composition.

The photocurable film according to exemplary embodiments may include a cured product of the photocurable composition.

In some embodiments, the photocurable film may include a base film and a hard coating layer disposed on the base film and including the cured product. For example, the photocurable film can be used as a hard coating film.

Image display devices according to example embodiments may include a cured product of the photocurable composition.

In some embodiments, the image display device may include a display panel, a polarizing layer disposed on the display panel, and a hard coating film disposed on the polarizing layer and including the cured product.

In one embodiment, the image display device may further include a retardation layer disposed between the display panel and the polarization layer.

Ketal-based compounds according to exemplary embodiments may include compounds represented by specific chemical formulas. Therefore, when the above-mentioned ketal-based compound is used as a photoinitiator, it can have high sensitivity to light and can have high activity even at a small exposure amount and low temperature, thereby initiating and promoting the polymerization reaction of the photopolymerizable compound.

Additionally, the photocurable composition according to exemplary embodiments may have high polymerization reactivity and facilitate the formation of a crosslinking network by including the above-described ketal-based compound as a photoinitiator. Therefore, the crosslink density of the photocurable film formed therefrom may be excellent, and the photocurable film may have high mechanical and optical properties.

Ketal-based compounds according to embodiments of the present invention may include compounds represented by specific chemical formulas.

Additionally, the photocurable composition according to exemplary embodiments may include a photoinitiator including the ketal-based compound. Therefore, the photocurable composition may have excellent sensitivity to light, polymerization reactivity, and stability over time, and a photocurable film having high crosslink density, surface hardness, and durability can be provided using the photocurable composition.

Additionally, an image display device including a photocurable film formed from the photocurable composition may be provided.

Hereinafter, the present invention will be described in detail.

<Ketal-based compounds>

Ketal-based compounds according to exemplary embodiments may include a compound represented by Formula 1 below or a compound represented by Formula 2 below.

[Formula 1]

[Formula 2]

In Formula 1, R ₁ and R ₂ may each independently be a hydrogen atom, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aliphatic hydrocarbon group with 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom.

Preferably, R ₁ and R ₂ may each independently be an aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom. In this case, as the tertiary amine group is located in the aromatic ring of the ketal-based compound, the reactivity and sensitivity of the ketal-based compound can be excellent, and an excellent polymerization initiation reaction can occur at a small exposure amount.

For example, R ₁ and R ₂ may each independently be an alkyl group with 1 to 10 carbon atoms, an alkenyl group with 2 to 10 carbon atoms, or an alkynyl group with 2 to 10 carbon atoms, and include an ether bond in the carbon chain. can do.

In one embodiment, R ₁ and R ₂ may be connected to each other to form a ring. For example, at least one of the carbon atoms of R ₁ may form a covalent bond with at least one of the carbon atoms of R ₂ .

For example, R ₁ and R ₂ together with the nitrogen atom connecting R ₁ and R ₂ are a heterocycloalkyl group having 3 to 22 atoms, a heterocycloalkenyl group having 3 to 22 atoms, or a hetero group having 3 to 22 atoms. It can form a cycloalkynyl group. As used herein, the term “heterocyclo” refers to a cyclic structure containing at least one heteroatom (eg, nitrogen, oxygen, or sulfur).

X may be a halogen atom, for example, X may be F, Cl, Br, I. Preferably, X may be F or Cl.

In Formula 2, R ₃ and R ₄ may each independently be a hydrogen atom, an aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with a hydrogen atom.

R ₅ and R ₆ may each independently be a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom.

Preferably, R ₃ and R ₄ may each independently be an aliphatic hydrocarbon group having 2 to 10 carbon atoms or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom, and more preferably, R ₃ to R ₆ may each independently be an aliphatic hydrocarbon group having 2 to 10 carbon atoms or an aliphatic hydrocarbon group having 1 to 10 carbon atoms in which at least one carbon atom is replaced with an oxygen atom.

For example, R ₃ to R ₆ may each independently be an alkyl group having 2 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms, and may include an ether bond in the carbon chain.

For example, when R ₃ and R ₄ are methyl groups, as the chain length of the alkyl group bonded to the tertiary amine group becomes shorter, the electron transfer characteristics of the aromatic ring due to the amine group may deteriorate. Therefore, the activity of the ketal-based compound may decrease and sensitivity to light may decrease. According to exemplary embodiments, as the carbon number of the alkyl chain connected to the tertiary amine group is 2 or more, the ketal-based compound may have high activity and photoreactivity may be further improved.

In one embodiment, R ₃ and R ₄ may be connected to each other to form a ring. For example, at least one of the carbon atoms of R ₃ may form a covalent bond with at least one of the carbon atoms of R ₄ . In one embodiment, R ₅ and R ₆ may be connected to each other to form a ring. For example, at least one of the carbon atoms of R ₅ may form a covalent bond with at least one of the carbon atoms of R ₆ .

For example, R ₃ and R ₄ , or R ₅ and R ₆ together with the nitrogen atom connecting R ₃ and R ₄ , or R ₅ and R ₆ are a heterocycloalkyl group having 3 to 22 atoms, or a heterocycloalkyl group having 3 to 22 atoms. It can form a heterocycloalkenyl group of 22 or a heterocycloalkynyl group of 3 to 22 atoms.

The compounds represented by Formula 1 and Formula 2 have a photoactive group, for example, a ketal moiety, contained in the molecular structure, and thus can generate radicals in response to irradiated light. Therefore, the ketal-based compound can form active radicals upon light irradiation and initiate a polymerization reaction of the photocurable composition.

For example, compounds represented by Formula 1 and Formula 2 have a carbonyl group in their molecular structure and can generate two different radicals when irradiated with light. For example, the compounds represented by Formula 1 and Formula 2 may be converted to an excited state by the carbonyl group absorbing light. In this case, the excited α-carbon bond is decomposed to form a radical, for example, methoxybenzyl radical and benzoyl radical.

The ketal-based compound can increase the activity of the photoinitiator due to the tertiary amine group bonded to the para-position of the aromatic ring, and can have excellent sensitivity and reactivity even with a small exposure amount. For example, a tertiary amine group can shift the electrons of an aromatic ring as an electron donor (Eletron Drawing Group, EDG), and a ketal-based compound can have high structural activity.

Additionally, as the tertiary amine group, which is an electron donor, is located at the end of the ketal-based compound, the electron density of the aromatic ring may increase. In this case, the decomposition energy of the α-carbon bond of the carbonyl group within the structure of the ketal-based compound can be lowered, and the formation of radicals according to light irradiation can be promoted. Therefore, the activation energy and curing temperature of the photocurable composition can be lowered, and the curing speed and conversion rate to a cured product according to light irradiation can be improved.

Additionally, a halogen atom such as F or Cl or a tertiary amine group may be bonded to the aromatic ring as a substituent to further increase the sensitivity of the photocurable composition. For example, as a halogen atom or tertiary amine group is located in the aromatic ring located at both ends of the ketal-based compound, the activity and reactivity of the ketal-based compound may increase. Therefore, when light is irradiated to the photocurable composition, photodecomposition of the ketal-based compound may be promoted and radical generation by photodecomposition may be facilitated.

Therefore, both surface curability and internal curability can be improved, and a photocurable film with a high crosslink density can be formed even if the curing process is carried out at a low light amount and temperature. In addition, structural deformation such as cracks and wrinkles of the photocured product can be prevented during the curing process, and it can have excellent surface hardness and adhesion to the substrate.

In some embodiments, the compound represented by Formula 1 may include at least one of the compounds represented by Formulas 1-1 to 1-18 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Formula 1-6]

[Formula 1-7]

[Formula 1-8]

[Formula 1-9]

[Formula 1-10]

[Formula 1-11]

[Formula 1-12]

[Formula 1-13]

[Formula 1-14]

[Formula 1-15]

[Formula 1-16]

[Formula 1-17]

[Formula 1-18]

Compounds represented by Formulas 1-1 to 1-18 may have high sensitivity to light because the aromatic rings located at both ends of the molecular structure each have a halogen atom and a tertiary amine group.

In some embodiments, the compound represented by Formula 2 may include at least one of the compounds represented by Formulas 2-1 to 2-8 below.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

[Formula 2-5]

[Formula 2-6]

[Formula 2-7]

[Formula 2-8]

Ketal-based compounds represented by Formulas 2-1 to 2-8 can have improved reactivity and activity to light by having tertiary amine groups bonded to both aromatic rings located at both ends of the molecular structure. Therefore, the photocurable composition can have high sensitivity to light, and can have excellent polymerization reactivity even at a small exposure amount and low temperature by facilitating the formation of a crosslinking network.

Therefore, a photocurable composition containing the ketal-based compound as a photoinitiator may have high sensitivity and activity to light, and a crosslinking network may be easily formed within the photocurable composition. Therefore, the surface hardness and internal hardness of the photocurable film can be excellent, and the crosslink density can be improved.

<Photocurable composition>

Photocurable compositions according to exemplary embodiments may include a photoinitiator including the ketal-based compound.

The photoinitiator may serve to initiate a polymerization reaction by light by providing photoactivity to the photocurable composition. For example, the photoinitiator may generate active radicals when irradiated with light, and a photopolymerization reaction may be initiated by the radicals generated from the photoinitiator.

In addition, as the photoinitiator contains the above-mentioned ketal-based compound, the photocurable composition may have excellent sensitivity to light, and both the surface and deep curing of the photocurable film may be excellent.

In some embodiments, the photoinitiator includes, in addition to the ketal-based compound, a benzophenone-based compound, a benzoin-based compound, a triazine-based compound, a biimidazole-based compound, a phosphine oxide-based compound, an oxime ester-based compound, an acetophenone-based compound, It may further include a thioxanthone-based compound, anthracene-based compound, or anthraquinone-based compound.

For example, the photopolymerization initiator may be 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one, 1-[4-(2-hydroxy- Ethylsulfanyl)-phenyl]-2-methyl-2-morpholin-4-yl-propan-1-one, 2-methyl-2-morpholin-4-yl-1-(4-pentylsulfanyl-phenyl )-Propan-1-one, 2-methyl-2-morpholin-4-yl-1-(4-phenylsulfanyl-phenyl)-propan-1-one, 1-(4-ethylsulfanylphenyl)- 2-Methyl-2-morpholin-4-yl-propan-1-one, 2-ethyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-hexan-1-one, 2-Methyl-2-morpholin-4-yl-1-(4-p-toylsulfanyl-phenyl)-propan-1-one, 1-(4-cyclohexylsulfanyl-phenyl)-2-methyl- 2-Morpholin-4-yl-propan-1-one, diphenyl ketone benzyldimethyl ketal, dimethoxy-2-phenylatetophenone, triphenylamine, 4,4-diaminobenzophenone, phosphine oxide phenylbis It may further include (2,4,5-trimethylbenzoyl) or diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide. These may be used alone or in combination of two or more.

In some embodiments, the content of the photoinitiator may be 0.1 to 5% by weight of the total weight of the photocurable composition, preferably 0.1 to 3% by weight, and more preferably 1 to 3% by weight. there is. If the photoinitiator content is less than 0.1% by weight, the sensitivity of the photocurable composition may decrease, and the crosslinking density and durability of the cured product may deteriorate. If the photoinitiator content exceeds 5% by weight, cracks and wrinkles may occur in the cured product due to excessive crosslinking, and the scratch resistance and uniformity of the photocurable film may deteriorate.

In some embodiments, a polymerization initiation aid may be additionally included to improve the sensitivity of the photocurable composition. The polymerization initiation aid can increase the polymerization reactivity of the photocurable composition upon light irradiation, and thus the processability and productivity of the photocurable film can be excellent. Examples of the polymerization initiation aid include amine compounds, carboxylic acid compounds, and organic sulfur compounds having a thiol group.

According to exemplary embodiments, the photocurable composition may include a photopolymerizable compound and a solvent.

The photopolymerizable compound may have a photopolymerizable functional group. For example, the photopolymerizable compound may react with radicals generated by a photoinitiator to form a crosslinking network within the photocurable composition. For example, the photopolymerizable functional group may include a hydroxy group, carboxyl group, glycidyl group, oxetane group, vinyl group, or (meth)acryloyl group.

In some embodiments, the photopolymerizable compound may include a (meth)acrylate-based compound. As used herein, the term “(meth)acrylate” is used to encompass acrylate or methacrylate.

As (meth)acrylate-based compounds have high reactivity with radicals formed from ketal-based compounds, the crosslinking reactivity of the photocurable composition can be improved.

In one embodiment, the (meth)acrylate-based compound may include a urethane (meth)acrylate compound, an epoxy (meth)acrylate compound, or a (meth)acrylic ester compound. These may be used alone or in combination of two or more.

For example, the urethane (meth)acrylate compound may be a compound formed by reacting an isocyanate-based compound and a hydroxyl (meth)acrylate-based compound.

The isocyanate-based compound may be a compound having at least one isocyanate group. For example, the isocyanate-based compounds include 4,4'-dicyclohexyl diisocyanate, hexamethylene diisocyanate trimer, 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, and 1,8-diisocyanate. Isocyanatooctane, 1,12-diisocyanatodecane, 1,5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane , trans-1,4-cyclohexene diisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene -1,4-diisocyanate, tetramethylxylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4 , 4'-oxybis(phenylisocyanate), trifunctional isocyanate derived from hexamethylene diisocyanate, trimethane propanol adduct toluene diisocyanate, acryloyl ethyl isocyanate, methacryloyl ethyl isocyanate, etc. These may be used alone or in combination of two or more.

The hydroxy group (meth)acrylate-based compound may be a (meth)acrylate compound having at least one hydroxy group. For example, the hydroxy group (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxy isopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and caprolactone ring-opening. It may include hydroxy(meth)acrylate, pentaerythritol tri/tetra(meth)acrylate mixture, dipentaerythritol penta/hexa(meth)acrylate mixture, etc. These may be used alone or in combination of two or more.

For example, the epoxy (meth)acrylate compound may be a compound formed by reacting a compound having an epoxy group and (meth)acrylic acid.

Examples of compounds having the above epoxy group include bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol AD-type epoxy resin, novolac-type epoxy resin, naphthalene-type epoxy resin, tris phenol methane-type epoxy resin, and glycidyl amine type. Epoxy resin, etc. can be mentioned. These may be used alone or in combination of two or more.

For example, the (meth)acrylic ester compounds include dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, pentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. Latex, (meth)acrylic ester, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethylene glycol di( meta)acrylate, propylene glycol (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, Neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(2-hydroxyethyl)iso Cyanurate di(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, isooctyl(meth)acrylate, isodexyl(meth)acrylate It may include acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, isoborneol (meth)acrylate, etc. These may be used alone or in combination of two or more.

In some embodiments, the content of the photopolymerizable compound may be 10 to 90% by weight, preferably 10 to 80% by weight, of the total weight of the photocurable composition. If the content of the photopolymerizable compound is less than 10% by weight, the hardness and degree of cross-linking of the photocurable film formed from the photocurable composition may be deteriorated. If the content of the photopolymerizable compound exceeds 90% by weight, the surface uniformity of the photocurable film may be reduced due to excessive crosslinking, and the wear resistance or scratch resistance may be deteriorated.

The solvent may be used without limitation as long as it can dissolve the photoinitiator and/or the photopolymerizable compound. By including the solvent, the viscosity of the photocurable composition can be lowered, and, for example, applicability, adhesion, and jetting properties to the base film can be improved.

For example, the solvent may include alcohols such as methanol, ethanol, isopropanol, butanol, methylcellusorb, and ethylsolusorb; Ketones such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, and cyclohexanone; Hexane such as hexane, heptane, and octane; Aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; esters such as 2-hydroxyethyl propionate, 2-hydroxy-2-methylethyl propionate, hydroxyethyl acetate, and methyl 2-hydroxy-3-methylbutanoate; Cyclic ethers such as tetrahydrofuran and pyran; Cyclic esters such as γ-butyrolactone; ethylene glycol monoalkyl ethers; Diethylene glycol dialkyl ethers; ethylene glycol alkyl ether acetate; alkylene glycol alkyl ether acetates; propylene glycol monoalkyl ethers; propylene glycol dialkyl ethers; propylene glycol alkyl ether propionates; Butyldiol monoalkyl ethers; Butanediol monoalkyl ether acetate; Butanediol monoalkyl ether propionates; It may include dipropylene glycol dimethyl ether, dipropylene glycol dialkyl ether, etc. These may be used alone or in combination of two or more.

The solvent may be included in the remaining amount excluding other components of the photocurable composition. For example, the solvent may be included in the remaining amount excluding the photoinitiator and photopolymerizable compound, or in the remaining amount excluding the photoinitiator, photopolymerizable compound, and other additive components.

In some embodiments, the content of the solvent may be 10 to 90% by weight of the total weight of the photocurable composition. Within the above range, the photocurable composition may have a low viscosity, thereby providing excellent applicability and workability, and has excellent polymerization reactivity during the curing process, thereby improving economic efficiency and productivity.

The photocurable composition according to exemplary embodiments may, if necessary, further include additives commonly used in the art in addition to the above components to the extent that they do not impair the properties of the above components. For example, the additive may include a photostimulant, antioxidant, ultraviolet absorber, light stabilizer, anti-aggregation agent, chain transfer agent, leveling agent, surfactant, lubricant, colorant such as pigment or dye, etc.

<Light film>

The photocurable film according to exemplary embodiments may include a cured product of the photocurable composition described above.

The photocurable film has excellent wear resistance, hardness, and optical properties, so it can be usefully used in image display devices such as liquid crystal displays and organic light emitting display devices. For example, it can function as an organic protective film on the substrate or underlying substrate of an image display device, and can be used as a hard coating layer, overcoating layer, window, etc.

The photocurable film can be formed by curing the photocurable composition described above by irradiating light. For example, after applying the photocurable composition described above on a base film, an exposure process may be performed to form a photocurable film.

Examples of the base film include cycloolefin-based derivatives having units of monomers containing cycloolefins such as norbornene or polycyclic norbornene-based monomers, diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, and isobutyl ester cellulose. , cellulose such as propionyl cellulose, butyryl cellulose or acetylpropionyl cellulose, ethylene-vinyl acetate copolymer, polyester, polystyrene, polyamide, polyetherimide, polyacrylic, polyimide, polyethersulfone, polysulfone, Polyethylene, polypropylene, polymethyl pentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, poly Examples include butylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, and epoxy.

In one embodiment, surface treatment, such as plasma treatment or corona treatment, may be performed on the base film to improve adhesion with the coating film.

In some embodiments, a coating film may be formed by applying the photocurable composition to one or both sides of the base film. Examples of application methods include die coat, slit coat, slit and spin coat, spin coat, air knife, reverse roll, spray, blade, casting, or inkjet printing. In one embodiment, after applying the photocurable composition on a base film to form a coating film, a pre-baking process may be performed to remove volatile components such as solvents.

Afterwards, an exposure process can be performed on the coating film to form a photocurable film. The exposure process may use an ultraviolet light source such as a high-pressure mercury lamp. In one embodiment, a development process may be further performed to pattern the photocurable film.

For example, during the exposure process, an exposure mask of a predetermined shape can be placed on the coating film to form a pattern having a desired shape. For example, ultraviolet rays may be irradiated to a portion of the coating film where the exposure mask is not placed, and a curing reaction may occur in the portion irradiated with ultraviolet rays, for example, an exposed portion. As the ultraviolet rays, g-rays (wavelength: 436 nm), h-rays (wavelength: 405 nm), i-rays (wavelength: 365 nm), etc. can be used.

In one embodiment, after the exposure process, a development process may be performed to form a desired pattern. For example, a cured pattern can be formed by removing non-exposed areas using an alkaline developer. The development process may include a liquid addition method, dipping method, spray method, etc. After the exposure process or the development process, a post-baking process may be further performed.

<Image display device>

Image display devices according to example embodiments may include the photocuring film described above. For example, the image display device may include a cured product of the photocurable composition described above. The photocurable film may be applied as a hard coating layer, window, or outermost protective layer of the image display device.

For example, the image display device may include a display panel, a polarizing layer disposed on the display panel, and a hard coating film disposed on the polarizing layer and including the cured product.

In one embodiment, the hard coating film may include a base layer and a hard coating layer formed on the base layer and including a cured product of the photocurable composition described above. In this case, the hard coating layer may be placed toward the user's viewing side. The term “viewer's side” used in this specification may refer to a side of an image display device adjacent to the direction in which the user is looking.

In one embodiment, the hard coating layer may be formed by applying the above-described photocurable composition directly on the polarizing layer and then curing it.

The polarizing layer may include a polyvinyl alcohol-based polarizer or a polarizing plate including a protective film attached to at least one surface of the polarizer. Alternatively, the polarizing layer may include a liquid crystal layer containing a liquid crystal compound, and may also include an alignment layer to provide orientation to the liquid crystal layer.

In some embodiments, at least one retardation film may be disposed on the polarizing layer. In this case, the retardation film may be disposed toward the display panel. For example, the retardation film may be disposed between the display panel and the polarizing layer.

In one embodiment, the retardation film may include a bipartite wavelength retardation layer. In one embodiment, the retardation film may have a multi-layer structure of a two-wavelength retardation layer and a quarter-wavelength retardation layer.

In one embodiment, the image display device includes a display panel, a quarter-wave retardation layer disposed on the display panel, a bi-wave retardation layer disposed on the quarter-wave retardation layer, and a polarized light disposed on the bi-wave retardation layer. layer, and a hard coating film disposed on the polarizing layer.

The display panel may include a liquid crystal display device or an organic light emitting diode (OLED) device, and may be used as a flat panel display, flexible display, or foldable display. For example, a display panel may include a pixel electrode, a pixel defining layer, a display layer, a counter electrode, and an encapsulation layer disposed on a panel substrate.

The image display device may include various image display devices such as a liquid crystal display device, an organic light emitting display device, an electroluminescence display device, a plasma display device, and a field emission display device, and may include, for example, a flexible display device having flexibility and bending properties. It may be a display device or a foldable display device.

Photocurable films formed from photocurable compositions according to exemplary embodiments may have high crosslink density and surface hardness, and may have excellent physical durability and thermal/chemical stability. Therefore, it can be applied to the hard coating layer to effectively protect the underlying substrate or structures.

Hereinafter, experimental examples including specific examples and comparative examples are presented to aid understanding of the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims, and do not limit the scope and technical idea of the present invention. It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope, and it is natural that such changes and modifications fall within the scope of the appended patent claims.

Synthesis example: Ketal-based compound

(1) Synthesis Example 1: A-1

As reaction monomers, 31.5 g (0.1 mol) of 1-(4-chlorophenyl)-2-(4-(pyrrolidin-1-yl)phenyl)ethane-1,2-dione and 53.3 g (0.1 mol) of trimethyl orthoformate ( 0.5 mol) was prepared. The reaction monomer was added to 100 ml of methanol and stirred. Afterwards, 20 g of sulfuric acid was slowly added dropwise and refluxed for 24 hours to react. After the reaction was completed, 40 g of triethylamine was slowly added dropwise, and the reaction solution was concentrated under reduced pressure. The concentrate was dissolved in ethyl acetate and then passed through diatomaceous earth. Afterwards, the filtered solution was concentrated under reduced pressure and recrystallized using normal hexane. Afterwards, the solid was recovered to obtain 32.7 g of compound (A-1) of the following formula 1-1.

[Formula 1-1]

The ketal-based compound of Formula 1-1 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 2.01 (4H, t, J = 7.0 Hz), 3.30 (6H, s), 3.26 (4H, t, J = 7.1 Hz), 6.48 (2H, d) , J = 9.1 Hz), 6.56 (2H, d, J = 8.9 Hz), 7.42 (2H, d, J = 8.9 Hz), 8.05 (2H, d, J = 9.1 Hz).

(2) Synthesis Example 2: A-2

Except that 34.5 g (0.1 mol) of 1-(4-chlorophenyl)-2-(4-(dipropylamino)phenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt were used as reaction monomers. Synthesis was performed in the same manner as Synthesis Example 1. Accordingly, 35.1 g of compound (A-2) of the following formula 1-6 was obtained.

[Formula 1-6]

The ketal-based compound of Chemical Formula 1-6 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 0.89 (6H, t, J = 6.6 Hz), 1.58-1.71 (4H, m), 1.65 (4H, t, J = 7.0), 3.26 (6H, s), 6.47 (2H, d, J = 9.1 Hz), 6.56 (2H, d, J = 8.9 Hz), 7.42 (2H, d, J = 8.9 Hz), 8.05 (2H, d, J = 9.1 Hz) .

(3) Synthesis Example 3: A-3

As reaction monomers, 31.0 g (0.1 mol) of 1-(4-fluorophenyl)-2-(4-(piperidin-1-yl)phenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt were used. Synthesis was performed in the same manner as Synthesis Example 1 except that it was used. Accordingly, 36.7 g of compound (A-3) of the following formula 1-11 was obtained.

[Formula 1-11]

The ketal-based compound of Chemical Formula 1-11 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 1.30-1.38 (6H, m), 1.60-1.71 (4H, m), 3.25 (6H, s), 6.50 (2H, d, J = 9.1 Hz) , 6.57 (2H, d, J = 8.9 Hz), 7.44 (2H, d, J = 8.9 Hz), 8.08 (2H, d, J = 9.1 Hz).

(4) Synthesis Example 4: A-4

As reaction monomers, 36.1 g (0.1 mol) of 1-(4-(bis(2-methoxyethyl)amino)phenyl)-2-(4-fluorophenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt ) was performed in the same manner as in Synthesis Example 1, except that ) was used. Accordingly, 34.4 g of compound (A-4) of the following formula 1-17 was obtained.

[Formula 1-17]

The ketal-based compound of Chemical Formula 1-17 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 3.21 (6H, s), 3.25 (6H, s), 3.64 (4H, t, J = 7.1 Hz), 4.05 (4H, t, J = 7.0 Hz) ), 6.50 (2H, d, J = 9.1 Hz), 6.57 (2H, d, J = 8.9 Hz), 7.44 (2H, d, J = 8.9 Hz), 8.08 (2H, d, J = 9.1 Hz).

(5) Synthesis Example 5: A-5

Synthesis except that 35 g (0.1 mol) of 1,2-bis(4-(pyrrolidin-1-yl)phenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt were used as reaction monomers. Synthesis was performed in the same manner as Example 1. Accordingly, 38.5 g of compound (A-5) of the following formula 2-1 was obtained.

[Formula 2-1]

The ketal-based compound of Formula 2-1 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 1.99-2.05 (8H, m), 3.16 (6H, s), 3.25-3.28 (4H, m), 3.32-3.36 (4H, m), 6.44 ( 2H, d, J = 9.1 Hz), 6.52 (2H, d, J = 8.9 Hz), 7.38 (2H, d, J = 8.9 Hz), 8.03 (2H, d, J = 9.1 Hz).

(6) Synthesis Example 6: A-6

Synthesized in the same manner as Synthesis Example 1, except that 38 g (0.1 mol) of 1,2-bis(4-morpholinophenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt were used as reaction monomers. was carried out. Accordingly, 37.5 g of compound (A-6) of the following formula 2-3 was obtained.

[Formula 2-3]

The ketal-based compound of Formula 2-3 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 2.44-2.49 (8H, m), 3.16 (6H, s), 3.27-3.31 (4H, m), 3.34-3.39 (4H, m), 6.44 ( 2H, d, J = 9.1 Hz), 6.52 (2H, d, J = 8.9 Hz), 7.38 (2H, d, J = 8.9 Hz), 8.03 (2H, d, J = 9.1 Hz).

(7) Synthesis Example 7: A-7

Same as Synthesis Example 1 except that 41 g (0.1 mol) of 1,2-bis(4-(dipropylamino)phenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt were used as reaction monomers. Synthesis was performed using this method. Accordingly, 36.2 g of compound (A-7) of the following formula 2-5 was obtained.

[Formula 2-5]

The ketal-based compound of Formula 2-5 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 1.04 (9H, t, J = 7.0 Hz), 1.84-1.91 (8H, m), 3.16 (6H, s), 3.78 (4H, t, J = 7.1 Hz ), 3.88 (4H, t, J = 7.1 Hz), 6.44 (2H, d, J = 9.1 Hz), 6.52 (2H, d, J = 8.9 Hz), 7.38 (2H, d, J = 8.9 Hz) ), 8.03 (2H, d, J = 9.1 Hz).

(8) Synthesis Example 8: A-8

Excluding the use of 47.3 g (0.1 mol) of 1,2-bis(4-(bis(2-methoxyethyl)amino)phenyl)ethane-1,2-dione and 53.3 g (0.5 mol) of trimethyl orthoform salt as reaction monomers. Then, synthesis was performed in the same manner as Synthesis Example 1. Accordingly, 36.2 g of compound (A-8) of the following formula 2-7 was obtained.

[Formula 2-7]

The ketal-based compound of Formula 2-7 obtained above was analyzed by ¹ H-NMR. ¹ H-NMR analysis data is as follows.

¹ H-NMR (400 MHz, Acetone-d6): δ 3.04 (12H, s), 3.16 (6H, s), 3.57 (4H, t, J = 7.1 Hz), 3.74 (4H, t, J = 7.1 Hz) ), 6.44 (2H, d, J = 9.1 Hz), 6.52 (2H, d, J = 8.9 Hz), 7.38 (2H, d, J = 8.9 Hz), 8.03 (2H, d, J = 9.1 Hz).

Examples and Comparative Examples

(1) Preparation of photocurable composition

A photocurable composition was prepared by mixing the ingredients listed in Table 1 below in the corresponding amounts (% by weight).

division
(weight%) photopolymerization initiator
(A) photopolymerizable compound
(B) menstruum
(C) Example 1 3(A-1) 25(B-1)
25(B-2) 47 Example 2 3(A-2) 25(B-1)
25(B-2) 47 Example 3 3(A-3) 25(B-1)
25(B-2) 47 Example 4 3(A-4) 25(B-1)
25(B-2) 47 Example 5 3(A-5) 25(B-1)
25(B-2) 47 Example 6 3(A-6) 25(B-1)
25(B-2) 47 Example 7 3(A-7) 25(B-1)
25(B-2) 47 Example 8 3(A-8) 25(B-1)
25(B-2) 47 Example 9 5(A-7) 25(B-1)
25(B-2) 45 Example 10 0.1(A-7) 25(B-1)
25(B-2) 49.9 Example 11 2(A-7)
1(A-9) 25(B-1)
25(B-2) 47 Example 12 1(A-7)
2(A-9) 25(B-1)
25(B-2) 47 Example 13 2(A-7)
1(A-10) 25(B-1)
25(B-2) 47 Example 14 2(A-7)
1(A-11) 25(B-1)
25(B-2) 47 Comparative Example 1 3(A-9) 25(B-1)
25(B-2) 47 Comparative Example 2 3(A-10) 25(B-1)
25(B-2) 47 Comparative Example 3 3(A-11) 25(B-1)
25(B-2) 47 Comparative Example 4 3(A-12) 25(B-1)
25(B-2) 47 Comparative Example 5 2(A-9)
1(A-10) 25(B-1)
25(B-2) 47 Comparative Example 6 2(A-9)
1(A-11) 25(B-1)
25(B-2) 47

The specific ingredient names listed in Table 1 are as follows.

Photopolymerization initiator (A)

A-1) Ketal-based compound prepared in Synthesis Example 1 above

A-2) Ketal-based compound prepared in Synthesis Example 2 above

A-3) Ketal-based compound prepared in Synthesis Example 3 above

A-4) Ketal-based compound prepared in Synthesis Example 4 above

A-5) Ketal-based compound prepared in Synthesis Example 5 above

A-6) Ketal-based compound prepared in Synthesis Example 6 above

A-7) Ketal-based compound prepared in Synthesis Example 7 above

A-8) Ketal-based compound prepared in Synthesis Example 8

A-9) 2, 2-dimethoxy-2-phenylacetophenone (Irgacure 651, manufactured by Ciba)

A-10) 2-Hydroxy-2-methyl-1-phenyl-1-propan-1one (Darocur 1173, manufactured by Ciba)

A-11) 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1one (Irgacure 907, manufactured by Ciba)

A-12) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO, manufactured by Ciba)

Photopolymerizable compound (B)

B-1) Dipentaerythol pentaacrylate (M500, manufactured by Miwon Corporation)

B-2) Pentaerythol triacrylate (M340, manufactured by Miwon Corporation)

Solvent (C)

Methyl ethyl ketone (MEK, manufactured by Daejeong Chemical)

(2) Manufacturing of photocurable film

The photocurable composition according to the Examples and Comparative Examples was applied by spin coating on a transparent base film (TAC) with a thickness of 80㎛, and then dried at 70°C for 1 minute. Afterwards, an ultra-high pressure mercury lamp (USH-250D, manufactured by Ushio Denki Co., Ltd.) was used as the ultraviolet light source, and light with a wavelength of 365 nm was irradiated at a light quantity of 500 mJ/cm ³ in an atmospheric atmosphere. Afterwards, it was heated in an oven at 150°C for 10 minutes to prepare a photocurable film with a thickness of 7㎛.

Experiment example

(1) Sensitivity evaluation of the composition

The photocurable compositions of Examples and Comparative Examples were applied on a 1 mm thick glass substrate (Eagle A mask pattern was placed on the coating film, and light with a wavelength of 365 nm was selectively irradiated with doses of 3 mJ/cm ² , 5 mJ/cm ² , and 10 mJ/cm ² , respectively. Afterwards, a pattern was formed by spray developing at 25°C for 60 seconds using a 0.5% by weight aqueous sodium carbonate solution. Afterwards, the formed pattern was observed to evaluate the sensitivity of the composition based on the shape of the pattern according to each exposure amount. The evaluation criteria are as follows.

The evaluation results are shown in Table 2 below.

<Evaluation criteria>

○: No tearing or peeling of the pattern was observed.

△: Tearing and peeling of the pattern were observed.

×: Pattern is developed and does not remain

division Exposure amount 3mJ/ ^cm2 5mJ/ ^cm2 10mJ/ ^cm2 Example 1 ○ ○ ○ Example 2 ○ ○ ○ Example 3 ○ ○ ○ Example 4 ○ ○ ○ Example 5 ○ ○ ○ Example 6 ○ ○ ○ Example 7 ○ ○ ○ Example 8 ○ ○ ○ Example 9 ○ ○ ○ Example 10 △ △ ○ Example 11 ○ ○ ○ Example 12 △ ○ ○ Example 13 ○ ○ ○ Example 14 ○ ○ ○ Comparative Example 1 × △ ○ Comparative Example 2 × △ ○ Comparative Example 3 △ △ ○ Comparative Example 4 × △ ○ Comparative Example 5 △ △ ○ Comparative Example 6 △ △ ○

(2) Pencil hardness evaluation

For the photocured films of Examples and Comparative Examples, a pencil hardness test was performed using a pencil hardness tester at a load of 500 g and an angle of 45° in accordance with JIS K5600. The pencil was a Mitsubishi product, and the experiment was performed five times per pencil hardness, and the maximum pencil hardness at which no more than two scratches appeared was expressed as the pencil hardness of the corresponding photocurable film.

The evaluation results are shown in Table 3 below.

(3) Scratch resistance evaluation

Surface scratch evaluation was performed on the photocured films of Examples and Comparative Examples using a steel wool tester (WT-LCM100, Protech, Korea). #0000s level was used for steel wool, and scratch resistance was tested by applying a load of 1kg/(2cm × 2cm) to the upper surface of the photocurable film and reciprocating 10 times.

After evaluation, the photocurable film was illuminated under fluorescent light in a dark room and the number of scratches on the surface was measured. The evaluation criteria are as follows.

The evaluation results are shown in Table 3 below.

<Evaluation criteria>

ⓞ: Less than 10

○: 10 or more and less than 20

△: 20 to 40

×: More than 40

(4) Adhesion evaluation

Adhesion was evaluated by performing a cross-cut test based on ASTM D 3359 on the photocurable films of Examples and Comparative Examples. Scratches measuring 6 horizontal × 6 vertical lines were made at 2 mm intervals on the surface of the photocurable film using a cross hatch cutter, and then an adhesion test tape (Nichiban tape, manufactured by Nichiban) was attached to the scratches. Afterwards, the tape was removed at an angle of 180° and the piece peeled off from the surface of the photocurable film was measured to evaluate adhesion. The results of the adhesion evaluation were expressed according to the standards of ASTM D 3359-97. The evaluation criteria are as follows.

The evaluation results are shown in Table 3 below.

<Evaluation criteria>

0B: Breaks into flakes and more than 65% falls off

1B: The ends and lattice of the cut area are separated and the area is more than 35% but less than 65%

2B: A small area is separated from the grid portion of the cut area, and the area is more than 15% but less than 35%.

3B: A small area is separated from the grid portion of the cut area, and the area is more than 5% but less than 15%.

4B: A small area is separated from the grid portion of the cut area, making the area less than 5%

5B: The ends of the cut portion are smooth and there is no lattice coming off.

division pencil hardness Scratch resistance Adhesion Example 1 3H ⓞ 4B Example 2 3H ⓞ 4B Example 3 3H ⓞ 4B Example 4 3H ⓞ 4B Example 5 4H ⓞ 4B Example 6 4H ⓞ 5B Example 7 4H ⓞ 4B Example 8 4H ⓞ 4B Example 9 3H ○ 4B Example 10 2H ○ 3B Example 11 4H ○ 4B Example 12 3H ○ 3B Example 13 4H ○ 4B Example 14 4H ○ 4B Comparative Example 1 2H △ 2B Comparative Example 2 2H △ 3B Comparative Example 3 1H × 2B Comparative Example 4 1H × 3B Comparative Example 5 2H △ 3B Comparative Example 6 2H △ 2B

Referring to Table 2, it can be seen that the photocurable composition according to exemplary embodiments includes the above-described ketal-based compound as a photoinitiator, and thus has excellent overall sensitivity to light. Therefore, it can be confirmed that the photocurable film can have excellent curing degree even with a small exposure amount, and that solvent resistance has been improved.

It can be confirmed that the photocurable composition according to the comparative examples does not contain the above-mentioned ketal-based compound and thus has low sensitivity to light. Therefore, it can be confirmed that sufficient curing reaction did not occur at a low exposure amount, and that the cured portion was peeled off or developed during the development process.

Referring to Table 3, it can be seen that the photocurable films according to exemplary embodiments have excellent overall pencil hardness, wear resistance, and adhesion. By including the above-mentioned ketal-based compound as a photoinitiator, it can have excellent crosslinking reactivity, and it can be confirmed that the mechanical properties are excellent due to excellent surface and internal curing.

In the case of Examples 5 to 8, in which all aromatic rings of the ketal-based compound have tertiary amine groups as substituents, it can be confirmed that pencil hardness and wear resistance are somewhat superior to Examples 1 to 4. The reactivity of radicals formed from the ketal-based compound may be increased by the tertiary amine group, and accordingly, the initiation of polymerization of the photocurable composition may become easier.

It can be seen that the photocurable film according to the comparative examples has overall deterioration in pencil hardness, wear resistance, and adhesion compared to the examples. For example, if the above-described ketal-based compound is not included as a photoinitiator, sensitivity to light and polymerization reactivity may decrease, resulting in lower surface hardness and crosslinking density.

Claims (16)

A photoinitiator comprising at least one of the compounds represented by Formula 1 and Formula 2 below:
[Formula 1]

[Formula 2]

(In Formula 1 and Formula 2, R ₁ and R ₂ are each independently an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 1 to 10 carbon atoms, and R ₁ and R ₂ may be connected to each other to form a ring,
X is F or Cl,
R ₃ and R ₄ are each independently an alkyl group having 2 to 10 carbon atoms or an alkoxyalkyl group having 1 to 10 carbon atoms, and R ₃ and R ₄ may be connected to each other to form a ring,
R ₅ and R ₆ are each independently an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 1 to 10 carbon atoms, and R ₅ and R ₆ may be connected to each other to form a ring.
delete delete The photoinitiator according to claim 1, comprising at least one of the compounds represented by the following formulas 1-1 to 1-18:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Formula 1-6]

[Formula 1-7]

[Formula 1-8]

[Formula 1-9]

[Formula 1-10]

[Formula 1-11]

[Formula 1-12]

[Formula 1-13]

[Formula 1-14]

[Formula 1-15]

[Formula 1-16]

[Formula 1-17]

[Formula 1-18]
.
The photoinitiator according to claim 1, comprising at least one of the compounds represented by the following formulas 2-1 to 2-8:
[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

[Formula 2-5]

[Formula 2-6]

[Formula 2-7]

[Formula 2-8]
.
delete A photocurable composition comprising the photoinitiator according to claim 1.
The method of claim 7, wherein the photoinitiator is a benzophenone-based compound, a benzoin-based compound, a triazine-based compound, a biimidazole-based compound, a phosphine oxide-based compound, an oxime ester-based compound, an acetophenone-based compound, a thioxanthone-based compound, and anthracene. A photocurable composition further comprising at least one of an anthraquinone-based compound and an anthraquinone-based compound.
The photocurable composition according to claim 7, wherein the content of the photoinitiator is 0.1 to 5% by weight based on the total weight of the photocurable composition.
The photocurable composition of claim 7, further comprising a photopolymerizable compound and a solvent.
The photocurable composition of claim 10, wherein the photopolymerizable compound includes a (meth)acrylate-based compound.
The photocurable composition according to claim 10, wherein the content of the photopolymerizable compound is 10 to 90% by weight based on the total weight of the photocurable composition.
A photocurable film comprising a cured product of the photocurable composition according to claim 7.
In claim 13,
base film; and
A photocurable film disposed on the upper surface of the base film and comprising a hard coating layer containing the cured product.
An image display device comprising a cured product of the photocurable composition according to claim 7.
In claim 15,
display panel;
a polarizing layer disposed on the display panel; and
An image display device disposed on the polarizing layer and comprising a hard coating film containing the cured product.