KR20240021325A - Adhesive film, optical member comprising the same and optical display apparatus comprising the same - Google Patents

Abstract

An adhesive film containing inorganic particles with a refractive index of 1.5 or more, a diffuse transmittance of 3% or more at a near-infrared wavelength, a haze of 5% or less, and a storage modulus of 0.2 MPa or less at -20°C, an optical member containing the same, and an optical member containing the same. An optical display device is provided.

Description

Adhesive film, optical member including same, and optical display device including same {ADHESIVE FILM, OPTICAL MEMBER COMPRISING THE SAME AND OPTICAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to an adhesive film, an optical member including the same, and an optical display device including the same.

As interest in foldable optical displays increases, adhesive films with excellent foldable properties are in demand. Adhesive films are used to adhere various optical elements to each other within an optical display device.

Currently, there is high demand for mobile foldable display devices such as mobile phones. Mobile foldable display devices are structured so that you can write or draw using a pen. At this time, in order to properly recognize the user's writing or picture, the adhesive film in the display device needs to have a near-infrared diffuse transmittance in a certain range.

Technologies for optical sheets that secure diffuse near-infrared transmittance have been developed. However, the development of an adhesive film that provides excellent folding properties while ensuring diffuse transmittance for near-infrared rays is insufficient. Meanwhile, the adhesive film is likely to be located on the outside of the optical display device, so the adhesive film needs to have excellent impact resistance to prevent damage to the panel from external impacts.

The background technology of the present invention is disclosed in Japanese Patent Publication No. 2013-072951, etc.

It is an object of the present invention to provide an adhesive film that provides excellent folding properties, low haze and excellent diffuse transmittance in the near infrared.

Another object of the present invention is to provide an adhesive film with excellent impact resistance.

One aspect of the present invention is an adhesive film.

The adhesive film contains inorganic particles with a refractive index of 1.5 or more, has a diffuse transmittance of 3% or more at near-infrared wavelengths, a haze of 5% or less, and a storage modulus at -20°C of 0.2 MPa or less.

Another aspect of the present invention is an optical member.

The optical member includes the adhesive film of the present invention.

Another aspect of the present invention is an optical display device.

The optical display device includes the adhesive film of the present invention.

The present invention provides an adhesive film that provides excellent folding properties, low haze, and excellent diffuse transmittance in the near infrared.

The present invention provides an adhesive film with excellent impact resistance.

Figure 1 is a schematic diagram of measuring peel force for an adhesive film according to an embodiment of the present invention.
Figure 2 is a schematic diagram of measuring impact resistance of an adhesive film according to an embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in more detail. However, the technology disclosed in this application is not limited to the embodiments described herein and may be embodied in other forms. However, the embodiments introduced here are provided to ensure that the disclosed content is thorough and complete and that the spirit of the present application can be sufficiently conveyed to those skilled in the art.

With reference to the attached drawings, the present invention will be described in detail by way of examples so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

As used herein, “(meth)acrylic” may mean acrylic and/or methacrylic.

As used herein, “copolymer” may include polymers or resins.

In this specification, the “refractive index” of the inorganic particles is a value measured in the visible light region, specifically at a wavelength of 633 nm. For example, the refractive index of inorganic particles can be measured by conventional methods known to those skilled in the art by referring to commercially available product catalogs.

As used herein, “near infrared wavelength” means a wavelength of 780 nm to 1400 nm.

“Diffractive transmittance” herein may be calculated according to ASTMD 1003. For example, the total light transmittance (TT _I ) and diffuse transmittance (DT I) are measured in a state filled with air without an adhesive film, and the total light transmittance (TT _II ) and diffuse transmittance (DT _I ) are measured in the presence of an adhesive film. _II ) was measured, and the diffusion transmittance of the adhesive film was calculated according to the formula below.

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Diffuse transmittance of adhesive film = DT _II - ((TT _II )-(DT _I )/(TT _I ))

In this specification, “haze” refers to a wavelength in the visible light region, for example, 380 nm to 780 nm.

In this specification, the "average particle diameter" of organic nanoparticles is the particle size of organic nanoparticles measured in aqueous or organic solvents with Malvern's Zetasizer nano-ZS equipment and expressed as a Z-average value, and the particle size confirmed during SEM/TEM observation. .

In this specification, “glass transition temperature of homopolymer” may refer to the glass transition temperature (Tg) measured using TA Instrument’s DSC Discovery for the homopolymer of the monomer to be measured. Specifically, for the homopolymer of the monomer to be measured, the temperature is raised to 180°C at a rate of 20°C/min, then gradually cooled to -100°C, and then raised to 100°C at a rate of 10°C/min. After obtaining data on the endothermic transition curve, the inflection point of the endothermic transition curve can be determined as the glass transition temperature.

When describing numerical ranges herein, “X to Y” means “X ≤ and ≤ Y.”

The present invention relates to an adhesive film that satisfies diffuse transmittance and low haze in a specific range of near-infrared wavelengths and at the same time has excellent folding properties. Additionally, the present invention relates to an adhesive film having excellent impact resistance.

Hereinafter, an adhesive film according to an embodiment of the present invention will be described.

The adhesive film (hereinafter referred to as 'adhesive film') according to this embodiment has a diffuse transmittance of 3% or more at a near-infrared wavelength, a haze of 5% or less, and a storage modulus of 0.2 MPa or less at -20°C.

The adhesive film has a diffuse transmittance of 3% or more in the near-infrared wavelength. Within the above range, when the adhesive film is mounted on a mobile display such as a mobile phone and used, operation can be smooth when writing or drawing with a pen or the like. Specifically, the adhesive film has a diffuse transmittance of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23. , 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 , 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73 , 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90%, specifically more than 3% but less than or equal to 90%, more specifically 3.2%. It can be from 10% to 10%.

The adhesive film has a haze of 5% or less. Within the above range, image display may not be affected when applied to an optical display device. Specifically, the adhesive film has a haze of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, It may be 4.6, 4.7, 4.8, 4.9, 5%, specifically 0% to 5%, more specifically 0.1% to 3%.

The adhesive film has a storage modulus of 0.2 MPa or less at -20°C. Within the above range, the adhesive film can provide excellent folding properties at low temperature, room temperature, and high temperature. Specifically, the adhesive film has a storage modulus of 0.001, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16 at -20℃. , 0.17 , 0.18, 0.19, 0.2MPa, 0.001MPa to 0.2MPa, more specifically 0.1MPa to 0.2MPa.

The adhesive film is formed from a composition for an adhesive film described below in order to provide a diffuse transmittance of 3% or more and a haze of 5% or less at a near-infrared wavelength while implementing the storage modulus at -20°C of the present invention. Hereinafter, the composition for an adhesive film of the present invention will be described in detail.

The composition for an adhesive film contains inorganic particles with a refractive index of 1.5 or more.

Inorganic particles with a refractive index of 1.5 or more can easily achieve a diffuse transmittance of 3% or more in the near-infrared wavelength of the adhesive film.

In one embodiment, the inorganic particles may have a refractive index of 1.5 to 2.5, for example 1.8 to 2.3, or 2.0 to 2.5 or 1.9 to 2.2. In the above range, the adhesive film can easily reach a diffuse transmittance of 3% or more and a haze of 5% or less at near-infrared wavelengths. This results from the difference in refractive index with the matrix for the adhesive film, which is formed by curing the remaining components except the inorganic particles with a refractive index of 1.5 or higher in the composition for the adhesive film described below.

Inorganic particles with a refractive index of 1.5 or more are impregnated in the matrix for the adhesive film, and the difference in refractive index between the inorganic particles with a refractive index of 1.5 or more and the matrix for the adhesive film is 0.4 to 1.1, for example, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. , 1.1, for example, may be 0.6 to 1.0. In the above range, the diffuse transmittance and haze ranges at near-infrared wavelengths of the adhesive film can be easily reached. The 'matrix for an adhesive film' is a cured product formed by curing the remaining components of the composition for an adhesive film, excluding the inorganic particles with a refractive index of 1.5 or higher and the inorganic particles with a refractive index of less than 1.5, which are explained below.

The present invention includes zinc-based oxide as inorganic particles with a refractive index of 1.5 or more. Zinc-based oxides, when included in a matrix for an adhesive film that achieves a storage modulus at -20°C as described below, have a diffuse transmittance of 3% or more and a haze of 5% at a near-infrared wavelength without affecting the storage modulus at -20°C. It was particularly easy to reach below %.

Zinc-based oxide may be zinc oxide alone or an aggregate containing zinc oxide and trace amounts of impurities.

Among the inorganic particles with a refractive index of 1.5 or more, zinc-based oxide may be included in 95% by weight or more, for example, 95% to 100% by weight, for example, 100% by weight, of the inorganic particles with a refractive index of 1.5 or more. Within the above range, the above-described effects of the present invention can be well implemented.

Inorganic particles with a refractive index of 1.5 or more may be spherical, amorphous, etc., and the average particle diameter (D50) is 10 nm to 300 nm, specifically 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120. , 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 nm, 30 nm to 200 nm. Within the above range, problems such as increased haze and decreased folding properties of the adhesive film can be reduced. In this specification, “average particle diameter (D50)” can be measured by a common method known to those skilled in the art. For example, the average particle size (D50) refers to the particle size corresponding to 50% of the particle size of inorganic particles in a weight cumulative analysis by a particle size analyzer.

In one embodiment, the inorganic particles having a refractive index of 1.5 or more may be contained alone as inorganic particles having an average particle diameter (D50) of 10 nm to 300 nm, specifically 120 nm to 200 nm.

In another embodiment, the inorganic particles having a refractive index of 1.5 or more may be a mixture of two or more types of inorganic particles having different average particle diameters (D50). For example, the inorganic particles having a refractive index of 1.5 or more include first inorganic particles having an average particle diameter (D50) of 10 nm to 300 nm, specifically 30 nm to 200 nm, and more specifically 120 nm to 200 nm; And it may be a mixture of second inorganic particles having an average particle diameter (D50) of 10 nm to 300 nm, specifically 10 nm to 100 nm. Among the inorganic particles having a refractive index of 1.5 or more, the weight ratio of the first inorganic particle to the second inorganic particle is 1:0.1 to 1:3, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1 :0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8 , 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1 :0.5 to 1:2.

Inorganic particles with a refractive index of 1.5 or more may not be surface treated or may be surface treated to improve compatibility with other organic components in the composition for an adhesive film. Surface treatment of inorganic particles with a refractive index of 1.5 or higher can be performed by conventional methods known to those skilled in the art.

Inorganic particles with a refractive index of 1.5 or more are present in an amount of 0.01% to 5% by weight in the adhesive film, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 , 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5% by weight, specifically 0.05% to 2% by weight. In the above range, the diffuse transmittance at near infrared wavelength, haze and storage modulus at -20°C of the adhesive film can be easily reached.

The inorganic particles with a refractive index of 1.5 or more are 0.01 to 2 parts by weight, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, based on 100 parts by weight of the monomer mixture described below. It may be included in amounts of 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 parts by weight, 0.05 parts by weight to 0.5 parts by weight. In the above range, the diffuse transmittance at near-infrared wavelength, haze and storage modulus at -20°C of the adhesive film can be easily reached.

The composition for an adhesive film further includes a polymer of a monomer mixture and an initiator.

The composition comprising a polymer of the monomer mixture and an initiator can be cured to form a matrix of an adhesive film.

The monomer mixture may include a (meth)acrylic monomer having an alkyl group and a (meth)acrylic monomer having a hydroxyl group.

An alkyl group-containing (meth)acrylic monomer can easily form the matrix of an adhesive film. In one embodiment, the alkyl group-containing (meth)acrylic monomer may be a linear or branched, unsubstituted alkyl group-containing (meth)acrylate having 1 to 10 carbon atoms at the ester moiety. For example, alkyl group-containing (meth)acrylic monomers include 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, propyl (meth)acrylate, and t-butyl ( Meth)acrylate, iso-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl At least one of (meth)acrylates, preferably at least one of 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, more preferably 2-ethylhexyl. It may contain (meth)acrylate.

The (meth)acrylic monomer containing an alkyl group may have a homopolymer glass transition temperature of -80°C to -20°C, specifically -80°C to -40°C. Within the above range, the adhesive film may have good folding properties at low temperatures, high temperatures, and high humidity.

The alkyl group-containing (meth)acrylic monomer may be included in the monomer mixture in an amount of 10% to 75% by weight, preferably 10% to 70% by weight, and 15% to 60% by weight. Within the above range, the adhesive film may have good bending reliability at low temperatures, high temperatures, and high humidity.

Hydroxyl group-containing (meth)acrylic monomers can easily provide peeling power of an adhesive film. The hydroxyl group-containing (meth)acrylic monomer may be a (meth)acrylate having 1 to 10 carbon atoms and containing one or more hydroxyl groups in the ester portion. For example, hydroxyl group-containing (meth)acrylic monomers include 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl. It may include one or more of (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, but is not limited thereto.

The hydroxyl group-containing (meth)acrylic monomer may have a homopolymer glass transition temperature of -70°C to 0°C, preferably -60°C to -10°C, and more preferably -50°C to -20°C. Within the above range, there may be an effect of increasing the peeling force and folding properties of the adhesive film.

The hydroxyl group-containing (meth)acrylic monomer may be included in the monomer mixture in an amount of 2% to 40% by weight, for example, 10% to 30% by weight, 2% to 20% by weight, or 5% to 20% by weight. . Within the above range, the adhesive strength and durability reliability of the adhesive film can be further improved.

The monomer mixture may further include an alkylene glycol group-containing (meth)acrylic monomer. The (meth)acrylic monomer containing an alkylene glycol group can easily provide excellent folding properties to an adhesive film by containing an alkylene glycol group. In this specification, “alkylene glycol group” means (alkylene-O- having 2 to 4 carbon atoms).

The (meth)acrylic monomer containing an alkylene glycol group has a homopolymer glass transition temperature of -90°C to -55°C, preferably -90°C to -60°C, more preferably -75°C to -60°C. You can. Within the above range, the modulus at low temperatures of the adhesive film can be lowered and the folding properties of the adhesive film at low temperatures can be improved. The alkylene glycol group-containing (meth)acrylate is a monofunctional acrylic having an ethylene oxide group (-CH ₂ CH ₂ O-) or a propylene oxide group (-CH ₂ CH ₂ CH ₂ O-), preferably an ethylene oxide group. May include rate.

The (meth)acrylic monomer having an alkylene glycol group may be, for example, an ether-based (meth)acrylate containing 1 mol or more, for example, 2 to 20 mol of ethylene glycol. Specifically, (meth)acrylate containing an ethylene glycol group is poly(ethylene glycol) methyl ether (meth)acrylate containing 6 to 13 moles of ethylene glycol, and poly(ethylene glycol) containing 2 to 10 moles of ethylene glycol. ) It may include one or more of ethylhexyl ether (meth)acrylate and poly(ethylene glycol) octyl ether (meth)acrylate containing 2 to 20 moles of ethylene glycol. Preferably, the alkylene glycol group-containing (meth)acrylate is di(ethylene glycol) 2-ethylhexyl ether (meth)acrylate, triethylene glycol 2-ethylhexyl ether (meth)acrylate, di(ethylene glycol). It may contain one or more types of octyl ether (meth)acrylate.

The alkylene glycol group-containing (meth)acrylic monomer may be included in the monomer mixture in an amount of 10% to 60% by weight, preferably 20% to 60% by weight, and more preferably 20% to 50% by weight. Within the above range, the repeatable folding properties of the adhesive film at low temperatures can be improved.

In one embodiment, the total of the alkyl group-containing (meth)acrylic monomer, the hydroxyl group-containing (meth)acrylic monomer, and the alkylene glycol group-containing (meth)acrylic monomer is 98% by weight or more in the monomer mixture, for example, 98% by weight to 100%. It may be a weight percent, for example 100 weight percent. Within the above range, it can be easy to implement the effects of the present invention.

The monomer mixture may further include an alkyl group-containing (meth)acrylic monomer, a hydroxyl group-containing (meth)acrylic monomer, and an alkylene glycol group-containing (meth)acrylic monomer and other co-monomers. Co-monomers can be included in the polymer to provide additional benefits to the adhesive film.

The co-monomer is a monomer different from the above-mentioned monomers, and includes a monomer having an amine group, a monomer having an alkoxy group, a monomer having a phosphoric acid group, a monomer having a sulfonic acid group, a monomer having a phenyl group, a monomer having a silane group, a monomer having a carboxylic acid group, and amide. It may contain one or more types of group-containing monomers.

Monomers having an amine group include monomethylaminoethyl acrylate, monoethylaminoethyl acrylate, monomethylaminopropyl acrylate, monoethylaminopropyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, N-tert- It may be an amine group-containing acrylic monomer such as butylaminoethyl acrylate and acryloxyethyltrimethylammonium chloride acrylate, but is not limited thereto.

Monomers having an alkoxy group include 2-methoxyethyl acrylate, 2-methoxypropyl acrylate, 2-ethoxypropyl acrylate, 2-butoxypropyl acrylate, 2-methoxypentyl acrylate, and 2-ethoxypentyl. Acrylate, 2-butoxyhexyl acrylate, 3-methoxypentyl acrylate, 3-ethoxypentyl acrylate, and 3-butoxyhexyl acrylate may be used, but are not limited thereto.

The monomer having a phosphoric acid group may be an acrylic monomer having a phosphoric acid group such as 2-methacryloyloxyethyldiphenyl phosphate acrylate, trimethyloyloxyethyl phosphate acrylate, and triacryloyloxyethyl phosphate acrylate. , but is not limited to this.

The monomer having a sulfonic acid group may be an acrylic monomer having a sulfonic acid group such as sodium sulfopropylacrylate, sodium 2-sulfoethyl acrylate, and sodium 2-acrylamido-2-methylpropanesulfonate, but is limited thereto. That is not the case.

The monomer having a phenyl group may be an acrylic vinyl monomer having a phenyl group such as p-tert-butylphenylacrylate, o-biphenyl acrylate, and phenoxyethyl acrylate, but is not limited thereto.

Monomers having a silane group include 2-acetoacetoxyethyl acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl tris(2-methoxyethyl)silane, vinyltriacetoxysilane, and acryloyloxypropyltrime. It may be a vinyl monomer with a silane group such as toxysilane, but is not limited thereto.

Monomers having a carboxylic acid group may include, but are limited to, acrylic acid, 2-carboxyethyl acrylate, 3-carboxypropyl acrylate, 4-carboxybutyl acrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid, and maleic anhydride. It doesn't work.

Amide group-containing monomers include acrylamide, N-methylacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N,N-methylenebisacrylamide, N-hydroxyethylacrylamide, and N,N- It may be diethylacrylamide, etc., but is not limited thereto.

The co-monomer may be included in an amount of 30% by weight or less, preferably 0% to 30% by weight, in the monomer mixture. It can be used to control adhesion to the adherend and to have optical properties.

The initiator may cure the composition for an adhesive film to form an adhesive film, or may polymerize the monomer mixture in the composition for an adhesive film and polymerize the remaining monomer. The initiator may include a photoinitiator, preferably a photoradical initiator.

Any photoinitiator can be used as long as it can induce the polymerization reaction of the radically polymerizable compound described below during the curing process by light irradiation or the like. For example, benzoin-based, hydroxy ketone-based, aminoketone-based, or phosphine oxide-based photoinitiators can be used, and specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. , Benzoin n-butyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxy acetophenone, 2,2'-dibutoxy acetophenone, 2-hyde. Acetophenone compounds such as oxy-2-methyl propiophenone, p-t-butyl trichloro acetophenone, p-t-butyl dichloro acetophenone, 4-chloro acetophenone, 2,2'-dichloro-4-phenoxy acetophenone, Dimethylanino acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1one, 2 -Benzyl-2-dimethyl amino-1-(4-morpholino phenyl)-butan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]- 2-Morphorino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4noncydiethyl Aminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2 -Chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylamino benzoic acid ester, oligo[2-hydroxy-2-methyl-1 -[4-(1-methylvinyl)phenyl]propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

The initiator may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.001 to 3 parts by weight, and more specifically 0.001 to 1 part by weight, based on 100 parts by weight of the monomer mixture. In the above range, the curing reaction can proceed completely, the remaining amount of initiator can remain, and the light transmittance of the adhesive film can be prevented from decreasing, and the generation of bubbles can be reduced and excellent reactivity can be achieved.

The composition for an adhesive film may further include inorganic particles with a refractive index of less than 1.5.

In one embodiment, inorganic particles with a refractive index of less than 1.5 may increase the impact resistance of the adhesive film rather than increasing the diffuse transmittance of the adhesive film at a near-infrared wavelength. In one embodiment, the adhesive film may have an initial height at which a dent occurs as a result of the impact resistance evaluation described below of 5 cm or more, for example, 5 cm to 10 cm. Within the above range, even if an adhesive film is laminated on a panel containing a light emitting device, damage to the panel due to external impact can be prevented. “Impact resistance” herein can be measured by the method described below.

Inorganic particles with a refractive index of less than 1.5 have a refractive index of 1.3 or more but less than 1.5, for example, 1.3, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.4, 1.41, 1.42, 1.43, 1.44, It can be 1.45, 1.46, 1.47, 1.48, 1.49, 1.3 to 1.49. Within the above range, the diffuse transmittance and haze at near-infrared wavelengths of the adhesive film may not be affected.

In one embodiment, the inorganic particles with a refractive index of less than 1.5 may be silica. For example, the silica may be solid silica, hollow silica, core-shell silica, etc.

Inorganic particles with a refractive index of less than 1.5 are spherical or amorphous, and their average particle diameter (D50) may be lower than that of the inorganic particles with a refractive index of 1.5 or more. Through this, impact resistance can be increased without affecting the diffuse transmittance at the near-infrared wavelength of the adhesive film.

Instead, inorganic particles with a refractive index of less than 1.5 may be included in an excessive amount in the adhesive film compared to inorganic particles with a refractive index of 1.5 or more. For example, inorganic particles with a refractive index of less than 1.5 are 10 to 30 times more expensive than inorganic particles with a refractive index of 1.5 or more, specifically 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22. , 23, 24, 25, 26, 27, 28, 29, 30 times, 20 to 30 times.

Specifically, inorganic particles with a refractive index of less than 1.5 have an average particle diameter (D50) of 1 nm to 50 nm, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14. , 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 , 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 nm, 5 nm to 30 nm. Within the above range, the effect of adding inorganic particles with a refractive index of less than 1.5 can be obtained.

Inorganic particles with a refractive index of less than 1.5 are present in an amount of 0.01% to 20% by weight of the adhesive film, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4. , 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20% by weight, 1% to 10% by weight, 1% to 5% by weight , may be included in 2% to 8% by weight. Within the above range, the impact resistance of the adhesive film can be improved and the effect of the present invention can be achieved.

Inorganic particles with a refractive index of less than 1.5 are used in an amount of 0.1 to 10 parts by weight, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, based on 100 parts by weight of the monomer mixture. , 5, 6, 7, 8, 9, 10 parts by weight, 1 part by weight to 5 parts by weight. Within the above range, the impact resistance of the adhesive film can be improved and the effect of the present invention can be achieved.

The composition for an adhesive film may further include organic nanoparticles.

Organic nanoparticles can increase the storage modulus of the adhesive film at high temperatures, preventing the adhesive film from peeling and/or lifting and/or generating bubbles at high temperatures, thereby further improving reliability at high temperatures. Organic nanoparticles have a high glass transition temperature and can increase the modulus of the adhesive film at high temperatures.

Organic nanoparticles may have an average particle diameter of 10 nm to 400 nm, specifically 10 nm to 300 nm, more specifically 30 nm to 280 nm, and even more specifically 50 nm to 280 nm. Within the above range, it does not affect the folding of the adhesive film, and the transparency of the adhesive film can be good with a total light transmittance of 90% or more in the visible light region.

The organic nanoparticle may have a refractive index difference between the polymer of the monomer mixture containing a (meth)acrylic monomer of 0.1 or less, specifically 0 or more and 0.05 or less, and specifically 0 or more and 0.02 or less. Within the above range, the transparency of the adhesive film may be excellent.

In one embodiment, the organic nanoparticles may have a refractive index of 1.35 to 1.70, specifically 1.40 to 1.60. Within the above range, the transparency of the adhesive film may be excellent.

Organic nanoparticles may include core-shell type as well as simple nanoparticles such as bead type, but are not limited thereto. In the case of a core-shell type, the core and shell may satisfy Equation 1 below: That is, both the core and shell may be nanoparticles made of organic material. When it has the above particle shape, the folding properties of the adhesive film are good and it can be effective in balancing elasticity and flexibility.

[Equation 1]

Tg(c) < Tg(s)

(In Equation 1 above, Tg(c) is the glass transition temperature of the core (unit: ℃), and Tg(s) is the glass transition temperature of the shell (unit: ℃).

In this specification, “shell” refers to the outermost layer of organic nanoparticles. The core may be a single spherical particle. However, the core may further include an additional layer surrounding the spherical particles if it has the above glass transition temperature.

Specifically, the glass transition temperature of the core may be -150°C to 10°C, specifically -150°C to -5°C, and more specifically -150°C to -20°C. In the above range, the adhesive film may have a low-temperature and/or room-temperature viscoelastic effect. The core may include one or more of polyalkyl acrylate, polysiloxane, or polybutadiene having the above glass transition temperature.

Polyalkyl acrylates include polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, polyisopropyl acrylate, polyhexyl acrylate, polyhexyl methacrylate, polyethylhexyl acrylate, and polyethyl acrylate. It may include one or more of hexyl methacrylate and polysiloxane, but is not necessarily limited thereto.

The polysiloxane can be, for example, an organosiloxane (co)polymer. Organosiloxane (co)polymers may be non-crosslinked or crosslinked (co)polymers. Cross-linked organosiloxane (co)polymers can be used for impact resistance and colorability. This is a cross-linked organosiloxane, and specifically, cross-linked dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, or a mixture of two or more thereof can be used. The refractive index can be adjusted to 1.41 to 1.50 by using a copolymerization of two or more organosiloxanes.

The crosslinking state of an organosiloxane (co)polymer can be judged based on the degree of solubility in various organic solvents. As the crosslinking state becomes more severe, the degree of dissolution by the solvent decreases. Acetone or toluene can be used as a solvent to determine the crosslinking state. Specifically, the organosiloxane (co)polymer may have a portion that is not soluble in acetone or toluene. The toluene insoluble content of the organosiloxane copolymer may be 30% or more.

Additionally, the organosiloxane (co)polymer may further include an alkylacrylate crosspolymer. The alkyl acrylate crosspolymer may include methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. For example, n-butyl acrylate or 2-ethylhexyl acrylate, which have a low glass transition temperature, can be used.

Specifically, the glass transition temperature of the shell may be 15°C to 150°C, specifically 35°C to 150°C, and more specifically 50°C to 140°C. Within the above range, the dispersibility of organic nanoparticles in an acrylic copolymer may be excellent. The shell may include polyalkyl methacrylate having the above glass transition temperature. For example, polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polyisopropyl methacrylate, polyisobutyl methacrylate, and polycyclohexyl methacrylate. It may include one or more of the rates, but is not necessarily limited thereto.

The core may be included in 30% to 99% by weight of the organic nanoparticles, specifically 40% to 95% by weight, and more specifically 50% to 90% by weight. Within the above range, the folding properties of the adhesive film may be good over a wide temperature range. The shell may be included in an amount of 1% to 70% by weight, specifically 5% to 60% by weight, and more specifically 10% to 50% by weight of the organic nanoparticles. Within the above range, the folding properties of the adhesive film may be good over a wide temperature range.

Organic nanoparticles may be included in the adhesive film at 0% to 20% by weight, specifically 0.1% to 20% by weight, specifically 0.5% to 12% by weight, and specifically 0.5% to 8% by weight. Within the above range, the modulus of the adhesive film at high temperature can be increased, the folding properties of the adhesive film at room temperature and high temperature can be improved, and the low temperature and/or room temperature viscoelasticity of the adhesive film can be excellent.

Organic nanoparticles may be included in an amount of 0 to 10 parts by weight, for example, 0.01 to 5 parts by weight, for example, 0.01 to 2 parts by weight, based on 100 parts by weight of the monomer mixture. Within the above range, the folding properties of the adhesive film at high temperatures may be improved.

Organic nanoparticles can be produced by conventional emulsion polymerization, suspension polymerization, and solution polymerization methods.

The composition for an adhesive film may further include a crosslinking agent.

A crosslinking agent can increase the degree of crosslinking of the adhesive composition and thereby increase the mechanical strength of the adhesive film.

The crosslinking agent may include a multifunctional (meth)acrylate that can be cured with active energy rays. For example, the crosslinking agent is 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, Neopentyl glycol adipate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, di(meth)acrylate ) Acryloxy ethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, dimethylol dicyclopentanedi(meth)acrylate, ethylene oxide modified hexahydrophthalic acid Di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, neopentyl glycol modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate or 9,9-bis[ difunctional acrylates such as 4-(2-acryloyloxyethoxy)phenyl]fluorene; Trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; Tetrafunctional acrylates such as diglycerol tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; Pentafunctional acrylates such as dipentaerythritol penta(meth)acrylate; and dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, or urethane (meth)acrylate (ex. isocyanate monomer and trimethylolpropane tri(meth)acrylate). Examples of reactants include hexafunctional acrylates, but are not limited thereto.

The crosslinking agent may be included in an amount of 0.001 to 5 parts by weight, specifically 0.003 to 3 parts by weight, and specifically 0.005 to 1 part by weight, based on 100 parts by weight of the monomer mixture or the polymer of the monomer mixture. In the above range, there is an effect of excellent peeling force and increased reliability.

The composition for an adhesive film may further include additives. Additives may include conventional additives known to those skilled in the art to be included in compositions for adhesive films. For example, the additive may include, but is not limited to, one or more of pigments, ultraviolet absorbers, leveling agents, and antistatic agents.

The adhesive film may have a peeling force of 500 gf/inch or more at 25°C, for example, 500 gf/inch to 3000 gf/inch. Within the above range, it can be easy for the adhesive film to provide excellent folding properties. In this specification, “peel force” refers to T-peel peel strength. The T-peel peel strength can be measured by the method measured in the following experimental example, and the adherend may be a glass plate, for example, an alkali-free glass plate.

The adhesive film may have a modulus of 0.1 MPa or less at 25°C, for example, 0.05 to 0.1 MPa. Within the above range, the adhesive film has good flexibility at room temperature, so bending reliability at room temperature may be excellent. The adhesive film may have a modulus of 0.1 MPa or less at 60°C, for example, 0.05 to 0.1 MPa.

The adhesive film may have a haze of 2% or less, specifically 0.1% to 1%, and a total light transmittance of 90% or more, specifically 95% to 99%, in the visible light region (e.g., wavelength 380 nm to 780 nm). Within the above range, optical transparency is good and can be used in optical display devices.

The adhesive film may have a thickness of 10 μm to 300 μm, specifically 20 μm to 100 μm. Within the above range, it can be used in optical display devices.

The composition for an adhesive film can be prepared by partially polymerizing the monomer mixture with an initiator and adding an additional initiator. The above-mentioned organic nanoparticles, cross-linking agents, additives, etc. may be further included. Partial polymerization may include solution polymerization, suspension polymerization, photopolymerization, bulk polymerization, or emulsion polymerization. Specifically, solution polymerization can be performed at 50 to 100°C by adding an initiator to the monomer mixture. The initiator may be an acetophenone series including 2,2-dimethoxy-2-phenylacetophenone, and a photopolymerization initiator such as 1-hydroxycyclohexylphenyl ketone. Partial polymerization may have a viscosity of 300 cPs to 50,000 cPs, specifically 500 cPs to 9,000 cPs at 25°C.

The adhesive film is a pressure-sensitive adhesive film and can be manufactured by conventional methods. For example, it can be manufactured by coating the composition for an adhesive film on a release film and then curing it. Curing is light curing and may include irradiation with a low-pressure lamp in an oxygen-free condition at a wavelength of 300 nm to 400 nm and an irradiation amount of 400 mJ/cm ² to 3000 mJ/cm ² .

An optical member according to an embodiment of the present invention includes an optical film and an adhesive film formed on at least one side of the optical film, and the adhesive film may include an adhesive film according to embodiments of the present invention. Accordingly, the optical member has good bending and/or folding properties and can be used in a flexible display device.

In one embodiment, an optical film provides certain optical functions in a display device, such as polarization, optical compensation, display quality improvement, and/or conductivity, and the optical film includes a window film, window, polarizer, color filter, and retardation film. , elliptical polarizing film, reflective polarizing film, anti-reflective film, compensation film, brightness enhancing film, alignment film, light diffusion film, glass scattering prevention film, surface protection film, OLED device barrier layer, plastic LCD substrate, ITO (indium tin oxide) , transparent electrode films containing fluorinated tin oxide (FTO), aluminum doped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowire, graphene, etc. The manufacturing method of the optical film can be easily manufactured by those skilled in the art to which the present invention pertains.

For example, a touch panel can be formed by attaching the touch pad to a window or optical film using an adhesive film. Alternatively, it can be applied as an adhesive film to a normal polarizing film as in the past.

In another embodiment, the optical film is an optically transparent optical film, and the optical member including the optical film and the adhesive film may function as a support layer for the display element. For example, the display element may include a window film, etc. The window film may include the optical member and a window coating layer (eg, a silicone-based coating layer) formed on the optical member. Specifically, the optical film has a total light transmittance of 90% or more in the visible light region and is made of cellulose resin including triacetylcellulose, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, etc. It may be a film formed of one or more of polyester resin, polycarbonate resin, polyimide resin, polystyrene resin, polyacrylate resin including polymethyl methacrylate, cyclic olefin polymer resin, acrylic resin, and polyamide resin. there is. The optical film may have a thickness of 10㎛ to 100㎛, specifically 20㎛ to 75㎛, more specifically 30㎛ to 50㎛. Within the above range, it can be used as a support layer for a display device.

The optical display device of the present invention may include the adhesive film of the present invention. The optical display device may include an organic light emitting diode display device, a liquid crystal display device, etc. The optical display device may include a flexible display device. However, the optical display device may also include a non-flexible display device.

Hereinafter, the configuration and operation of the present invention will be described in more detail through examples of the present invention. However, the following examples are intended to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Example 1

As shown in Table 1 below, 100 parts by weight of the monomer mixture was prepared, 0.005 parts by weight of the photoinitiator Irgacure651 was added, and then mixed well in the reactor. After exchanging dissolved oxygen in the reactor with nitrogen gas, the monomer mixture was partially polymerized by irradiating it with ultraviolet rays using a low-pressure mercury lamp for several minutes to prepare a composition containing a partial (meth)acrylic copolymer of the monomer mixture. To the composition, as shown in Table 1 below, 0.3 parts by weight of the photoinitiator Irgacure651 was added and 0.2 parts by weight of zinc oxide (ZnO, average particle diameter (D50) 150 nm, refractive index: 2.0) was added and mixed to prepare a composition for an adhesive film.

The composition for an adhesive film is applied to a PET (polyethylene terephthalate) film as a release film, the obtained coating layer is covered with a PET film as a release film, and irradiated with ultraviolet rays at an amount of 2000 mJ/cm ² to form PET film-adhesive film-PET. An adhesive sheet of the film was prepared.

Example 2

After partial polymerization in Example 1, 0.3 parts by weight of photoinitiator Irgacure651, 0.1 part by weight of zinc oxide (ZnO, average particle diameter (D50) 150 nm, refractive index: 2.0), zinc oxide (ZnO, average particle diameter (D50) 40 nm, refractive index: 2.0) An adhesive sheet was prepared in the same manner as in Example 1, except that an adhesive film was prepared by including 0.1 parts by weight of silica (SiO ₂ , average particle diameter (D50) 15 nm, refractive index: 1.46).

Example 3

Except that in Example 2, 0.2 parts by weight of zinc oxide (ZnO, average particle diameter (D50) 120 nm, refractive index: 2.0) and 5 parts by weight of silica (SiO ₂ , average particle diameter (D50) 15 nm, refractive index: 1.46) were included. An adhesive sheet was manufactured in the same manner as Example 2.

Example 4

Organic nanoparticles were prepared by emulsion polymerization method. The core is polybutylacrylate, the shell is polymethyl methacrylate, the shell is 35% by weight of the organic nanoparticles, the core is 65% by weight of the organic nanoparticles, the average particle diameter (D50) is 100nm, and the refractive index is 1.48. Organic nanoparticles were prepared.

In Example 2, 0.2 parts by weight of zinc oxide (ZnO, average particle diameter (D50) 150 nm, refractive index: 2.0), 5 parts by weight of silica (SiO ₂ , average particle diameter (D50) 15 nm, refractive index: 1.46), organic nanoparticles (average particle diameter (D50) 100 nm, refractive index: 1.48) An adhesive sheet was manufactured in the same manner as in Example 2, except that 0.1 part by weight was included.

Comparative Example 1 and Comparative Example 2

An adhesive sheet was manufactured in the same manner as in Example 2, except that the composition of the adhesive film composition in Example 2 was changed as shown in Table 1 below.

Comparative Example 3

An adhesive sheet was prepared in the same manner as in Example 1, except that antimony tin oxide (ATO, average particle diameter: 40 nm, refractive index: 1.69) was used instead of zinc oxide and the content was changed as shown in Table 1 below. Manufactured.

Comparative Example 4

An adhesive sheet was prepared in the same manner as in Example 1, except that magnesium oxide (MgO, average particle diameter: 100 nm, refractive index: 1.74) was used instead of zinc oxide and the content was changed as shown in Table 1 below. did.

Comparative Example 5

Organic nanoparticles were prepared in the same manner as in Example 4.

An adhesive sheet was prepared in the same manner as in Example 1, except that the organic nanoparticles (refractive index 1.48, average particle diameter (D50) 100 nm) prepared above were used instead of zinc oxide.

The composition of the adhesive films of Examples and Comparative Examples is shown in Table 1 below. The physical properties shown in Table 1 below were evaluated using the adhesive sheets of Examples and Comparative Examples.

(1) Diffuse transmittance at near-infrared wavelength (unit: %): All PET release films were peeled from the adhesive sheets of Examples and Comparative Examples to obtain adhesive films. For the adhesive film, the diffuse transmittance at the near-infrared wavelength was measured according to the above equation using a UV spectrometer and an integrating sphere according to ASTMD 1003.

(2) Haze (unit: %): All PET films were peeled from the adhesive sheet to obtain an adhesive film, and a Haze meter (Nippon Denshoku model NDH 5000) was used. Haze of adhesive films according to ASTM (American Society for Testing and Measurement) Test Method D 1003-95 5 (“Standard Test for Haze and Luminous Transmittance of Transparent Plastic”) was measured.

(3) Storage modulus (unit: MPa): Viscoelasticity was measured under auto strain conditions at a shear rate of 1 rad/sec and strain of 1% using ARES (Anton Paar MCR-501), a dynamic viscoelasticity measurement device. After removing all of the PET release film from the adhesive sheet, the adhesive film was laminated to a thickness of 500㎛, and the laminate was perforated with a hole puncher with a diameter of 8mm and used as a specimen. The storage modulus was measured from -60°C to 90°C at a temperature increase rate of 5°C/min, and the storage modulus was determined at -20°C, 25°C, and 60°C.

(4) Peeling force to glass plate (unit: gf/25mm): The adhesive sheets of Examples and Comparative Examples were cut into (width x height, 100 mm x 25 mm). A PET (polyethylene terephthalate) film of width One side of the PET film is released from the cut adhesive sheet, a glass plate (width A specimen for measuring peel force was prepared by laminating PET films (width

The specimen was autoclaved at a pressure of 3.5 bar and 50°C for 1000 seconds, and the specimen was fixed in the TA.XT_Plus Texture Analyzer (Stable Micro System). Referring to Figure 1 (b), in the TA.XT_Plus Texture Analyzer, the T-Peel peel strength (180° peel test) was measured.

(5) Folding characteristics: A module specimen was produced by stacking window film, adhesive film, polarizer, adhesive film, and OLED panel in that order. When manufacturing the module, the following window film, adhesive film, polarizer, adhesive film, and OLED panel were used, and the adhesive film was laminated on a polyimide-based film among the OLED panels:

-Window film: Replaced with PET film (thickness: 100㎛, Cosmoshine TA015, Toyobo).

-Adhesive film: Adhesive film prepared in Examples and Comparative Examples (thickness: 15㎛)

-Polarizer: PVA resin dyed with iodine was used. An 80 ㎛ thick polyvinyl alcohol film (degree of saponification: 99.5, degree of polymerization: 2000) was immersed in a 0.3% iodine aqueous solution and dyed, and then MD stretched to a draw ratio of 5.0. The stretched polyvinyl alcohol film was then immersed in a 3% boric acid solution and a 2% potassium iodide aqueous solution to correct its color, and then dried at 50°C for 4 minutes to prepare a polarizer (thickness 25 ㎛).

-OLED panel: Replaced with polyimide-based film (thickness: 100㎛, Cosmoshine TA015, Toyobo).

When the manufactured module specimen was cut into length x width 170mm x 110mm and folded 100,000 times at -20°C, it was evaluated whether bubbles, cracks, and delamination occurred in the module specimen. When folding, the module specimen was folded in the longitudinal direction and the OLED panel direction, and the curvature radius during folding was 1.5 mm and 30 cycles of folding per minute. In this case, 1 cycle means folding the specimen to the curvature radius and unfolding it at 180°. If no bubbles, cracks, or delamination occurred, it was evaluated as good; if one or more of bubbles, cracks, or delamination occurred, it was evaluated as bad.

(6) Impact resistance (unit: cm): Impact resistance is measured with reference to FIG. 2. After peeling off one PET film of the adhesive sheets prepared in Examples and Comparative Examples, a polyimide-based film (thickness: 50㎛, product name, manufacturer) was laminated on the peeled side. After peeling off the remaining release PET film of the adhesive sheet, polyethylene terephthalate film (thickness: 100㎛, product name, manufacturer) is laminated on the peeled side, and polyethylene terephthalate film (30), adhesive film (20), and polyimide-based The specimen shown in A of FIG. 2 in which films 10 were sequentially stacked was prepared. A pen 40 with a diameter of 0.7 mm and a circular cross-section was dropped from the upper surface of the polyimide film 10 in the direction of the arrow (vertical direction) in FIG. 2. As shown in B of FIG. 2, the polyethylene terephthalate-based film 30 and the adhesive film 20 are removed, and whether dents occur in the polyimide-based film 10 using a 3D microscope (VK-X1100, Keyence Company). The first height at which compression began to occur was measured. The higher the initial height, the better the impact resistance. When the impact resistance value measured in Comparative Example 2 is referred to as the reference value, the difference between the measured impact resistance value and the reference value is described. △1 means that the impact resistance value is 1cm higher than the standard value, and 0 means that the impact resistance value is the same as the standard value. △1 can be 5 to 10 cm when evaluating impact resistance.

Example Comparative example One 2 3 4 One 2 3 4 5 monomer EHA 60 60 60 60 60 60 60 60 60 HBA 15 15 15 15 15 15 15 15 15 EHDG 25 25 25 25 25 25 25 25 25 initiator 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 zinc oxide 150nm 0.2 0.1 0 0.2 0 0 0 0 0 zinc oxide 120nm 0 0 0.2 0 0 0 0 0 0 zinc oxide 40nm 0 0.1 0 0 0 0 0 0 0 silica 15nm 0 5 5 5 5 0 0 0 0 ATO 40nm 0 0 0 0 0 0 0.2 0 0 MgO 100nm 0 0 0 0 0 0 0 0.2 0 Organic Nanoparticles 100nm 0 0 0 0.1 0 0 0 0 5 Near-infrared diffuse transmittance 3.3 3.2 3.3 3.5 1.2 0.5 2.7 3.0 0.5 Haze 2.2 2.3 2.6 3.0 1.4 0.4 6.9 5.8 0.5 storage modulus -20℃ 0.10 0.14 0.11 0.13 0.10 0.08 0.14 0.16 0.11 25℃ 0.04 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.03 60℃ 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 Peel force 540 510 530 610 540 480 650 640 550 Folding characteristics OK OK OK OK OK OK OK OK OK impact resistance 0 △1 △1 △1 △1 0 0 0 0

*In Table 1 above, EHA: 2-ethylhexyl acrylate, HBA: 4-hydroxybutyl acrylate, EHDG: di(ethylene glycol) 2-ethylhexyl ether acrylate

As shown in Table 1, the adhesive film of the present invention provided excellent folding properties, low haze, excellent diffuse transmittance in the near infrared, and had excellent impact resistance.

On the other hand, the adhesive film of the comparative example did not provide all the effects of the present invention.

Simple modifications or changes to the present invention can be easily implemented by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (20)

An adhesive film comprising inorganic particles with a refractive index of 1.5 or more, a diffuse transmittance of 3% or more at a near-infrared wavelength, a haze of 5% or less, and a storage modulus of 0.2 MPa or less at -20°C.
The adhesive film of claim 1, wherein the adhesive film has a peeling force of 500 gf/inch or more at 25°C.
The adhesive film of claim 1, wherein the adhesive film has a storage modulus of 0.1 MPa or less at 25°C.
The adhesive film of claim 1, wherein the adhesive film has a storage modulus of 0.1 MPa or less at 60°C.
The adhesive film of claim 1, wherein the inorganic particles having a refractive index of 1.5 or more include zinc-based oxide.
The adhesive film of claim 5, wherein the zinc-based oxide is included in 95% by weight or more of the inorganic particles with a refractive index of 1.5 or more.
The adhesive film of claim 5, wherein the zinc-based oxide has an average particle diameter (D50) of 10 nm to 300 nm.
The adhesive film of claim 5, wherein the zinc-based oxide is included as a mixture of zinc-based oxides having different average particle diameters (D50).
The adhesive film according to claim 1, wherein the inorganic particles having a refractive index of 1.5 or more are contained in an amount of 0.01% by weight to 5% by weight of the adhesive film.
The adhesive film of claim 1, wherein the adhesive film further includes inorganic particles with a refractive index of less than 1.5.
The adhesive film of claim 10, wherein the inorganic particles having a refractive index of less than 1.5 include silica.
The adhesive film of claim 10, wherein the inorganic particles having a refractive index of less than 1.5 are contained in an amount of 0.01% to 20% by weight of the adhesive film.
The adhesive film of claim 10, wherein the adhesive film is formed from a composition for an adhesive film comprising inorganic particles having a refractive index of 1.5 or more, inorganic particles having a refractive index of less than 1.5, a polymer of a monomer mixture, and an initiator.
The adhesive film of claim 13, wherein the polymer of the monomer mixture is a polymer of a monomer mixture containing an alkyl group-containing (meth)acrylic monomer and a hydroxyl group-containing (meth)acrylic monomer.
The adhesive according to claim 13, wherein the polymer of the monomer mixture is a polymer of a monomer mixture containing an alkyl group-containing (meth)acrylic monomer, a hydroxyl group-containing (meth)acrylic monomer, and an alkylene glycol group-containing (meth)acrylic monomer. film.
The method of claim 15, wherein the monomer mixture contains 10% to 75% by weight of the alkyl group-containing (meth)acrylic monomer, 2% to 40% by weight of the hydroxyl group-containing (meth)acrylic monomer, and the alkylene glycol group-containing (meth)acrylic monomer. ) An adhesive film containing 10% to 60% by weight of an acrylic monomer.
The adhesive film of claim 13, wherein the composition for the adhesive film further includes organic nanoparticles.
The adhesive film of claim 17, wherein the organic nanoparticles include core-shell type organic nanoparticles that satisfy the following equation 1:
[Equation 1]
Tg(c) < Tg(s)
(In Equation 1 above, Tg(c) is the glass transition temperature of the core (unit: ℃), and Tg(s) is the glass transition temperature of the shell (unit: ℃).
An optical member comprising the adhesive film of any one of claims 1 to 18.
An optical display device comprising the adhesive film of any one of claims 1 to 18.

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