KR102585553B1 - Adhesive film, optical member comprising the same and optical display apparatus comprising the same - Google Patents

Abstract

An adhesive film containing a (meth)acrylic binder, a photoreactive monomer, and a photoinitiator, wherein the adhesive film has an adhesive force change rate of Formula 1 of 90% or more, and the adhesive film has a refractive index of 1.55 or more, comprising the same. An optical member and an optical display device including the same are 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.

In an organic light emitting device display device, more than 80% of the light emitted from the light emitting layer is reflected or absorbed at the interface or inside the various layered structures of the light emitting device or display device, and thus does not come out to the front of the display device and is lost. This lowers light extraction efficiency, which inevitably increases power consumption to achieve the desired luminance, which also shortens the lifespan of the light-emitting device.

Meanwhile, the touch screen panel laminated on the light emitting device is made of metal materials such as aluminum and titanium and has a high refractive index that is significantly higher than that of a typical adhesive film. For this reason, in order to increase light extraction efficiency by lowering the refractive index difference between layers, a method of additionally laminating a layer that can alleviate the refractive index difference or a high refractive index adhesive film may be considered.

The high refractive index adhesive film is manufactured in the form of an adhesive sheet in which a base film, a high refractive index adhesive film, and a release film are sequentially laminated, and then only the release film is peeled off and laminated on the adherend. A film that has not been release treated may be used as the base film. When a release-treated film is used as the base film, problems with the appearance of the adhesive film may occur. An assembly process using the adhesive sheet with an adherend including a display panel will be described with reference to FIG. 3.

Referring to FIG. 3, in (i), only the release film is peeled from an adhesive sheet in which the base film 30, the high refractive index adhesive film 50, and the release film are sequentially stacked, and then the display includes a high refractive index functional layer. It is laminated on the panel 10. In (ii), the adherend 40 including an optical film or the like is laminated on the base film 30 via the adhesive film 60. However, there is a problem that the thickness of the optical display device increases due to the base film 30 and the adhesive film 60.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-1189698, etc.

The purpose of the present invention is to provide an adhesive film having a high refractive index and variable adhesive force by UV irradiation.

Another object of the present invention is to provide an adhesive film that has a high refractive index and whose adhesion to the base film is significantly reduced by UV irradiation.

Another object of the present invention is to provide an adhesive film that has a high refractive index and whose adhesiveness to the base film is significantly reduced and adhesiveness to the adherend is significantly increased by UV irradiation.

Another object of the present invention is to provide an adhesive film with excellent optical properties and step filling properties.

Another object of the present invention is to provide an adhesive film that provides a thickness reduction effect for an optical display device.

One aspect of the present invention is an adhesive film.

1. The adhesive film includes a (meth)acrylic binder, a photoreactive monomer, and a photoinitiator, and the adhesive film has an adhesive force change rate of 90% or more according to the following formula 1, and the adhesive film has a refractive index of 1.55 or more:

[Equation 1]

Adhesion change rate = [(A - B)/A] x 100

(In Equation 1 above,

A is the adhesive force (unit: gf/inch) when peeling the base film from the adhesive film after laminating the laminate of the adhesive film and base film on a glass plate,

B is the adhesive force (unit: gf/inch) when the laminate of the adhesive film and the base film is laminated on a glass plate, irradiated with UV, and then the base film is peeled from the adhesive film.

In 2.1, A in Equation 1 may be 1000 gf/inch or more, and B in Equation 1 may be 100 gf/inch or less.

In 3.1-2, the adhesive film may have an adhesive force change rate of 10% or more in the following equation 2:

[Equation 2]

Adhesion change rate = [(D - C)/C] x 100

(In Equation 2 above, C is the adhesive force of the adhesive film to the glass plate (unit: gf/inch) measured by laminating a laminate of a base film and an adhesive film on a glass plate,

D is the adhesion of the adhesive film to the glass plate after laminating the laminate of the base film and the adhesive film on the adherend and irradiating it with UV (unit: gf/inch)).

In 4.3, C in Equation 2 may be 500 gf/inch or more, and D in Equation 2 may be 600 gf/inch or more.

In 5.1-4, the (meth)acrylic binder includes a (meth)acrylic copolymer of a monomer mixture including an aromatic group-containing (meth)acrylic monomer, a hydroxyl group-containing (meth)acrylic monomer, and an alkyl group-containing (meth)acrylic monomer. can do.

In 6.1-5, the (meth)acrylic binder includes a (meth)acrylic copolymer of a monomer mixture, and in the monomer mixture, the aromatic group-containing (meth)acrylic monomer is 30% to 95% by weight, hydroxyl group-containing ( The meth)acrylic monomer may be 5% to 30% by weight, and the alkyl group-containing (meth)acrylic monomer may be 0% to 40% by weight.

In 7.1-6, the photoinitiator may be included in 0.1% to 5% by weight of the adhesive film.

In 8.1-7, the adhesive film may further include inorganic particles.

At 9.8, the inorganic particles may include inorganic particles with a refractive index of 1.5 or more.

10.8-9, the inorganic particles may include zirconia.

11.8-10, the inorganic particles in the adhesive film may be included in an amount of 5% to 80% by weight.

12.8-11, the inorganic particles may include surface-treated inorganic particles.

In 13.1-12, the photoreactive monomer may be included in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the (meth)acrylic binder in the adhesive film.

In 14.1-13, the aromatic group-containing (meth)acrylic monomer may include a (meth)acrylic monomer of the following formula (1):

[Formula 1]

CH ₂ =C(R ¹ )-C(=O)-O-(R ² ) _n -Ar

(In Formula 1 above,

R ¹ is hydrogen or methyl group,

R ² is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms or a substituted or unsubstituted alkyleneoxy group having 1 to 10 carbon atoms,

Ar is a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms,

n is an integer from 0 to 3).

15.1-14, the photo-reactive monomer may include bifunctional or higher (meth)acrylate.

In 16.1-15, the bifunctional or higher (meth)acrylate 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 (meth)acrylate, di(meth)acryloxy ethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, dimethylol dicyclopentanedi(meth)acrylate Rate, ethylene oxide modified hexahydrophthalic acid di(meth)acrylate, tricyclodecane dimethanol(meth)acrylate, neopentyl glycol modified trimethylpropane di(meth)acrylate, adamantane di(meth) Acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modification Dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, tris(meth)acrylate ) Acryloxyethyl isocyanurate, diglycerin tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; Dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, 1 of 6 functional urethane (meth)acrylates It may include more than one species.

17.1-16, the adhesive film may further include a crosslinking agent.

18.1-17, the adhesive film further includes a UV absorber, and the adhesive film may have a light transmittance of 70% or less at a wavelength of 390 nm or less.

19.1-18, the adhesive film may have a glass transition temperature of -50°C to 15°C.

Another aspect of the present invention, an optical member, includes the adhesive film of the present invention.

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

21. The optical display device includes a display panel including one or more functional layers with a refractive index of 1.5 to 2; first adhesive film; and an optical film, wherein the first adhesive film includes the adhesive film of the present invention.

In 22.21, a base film may not be included between the optical film and the first adhesive film.

23.21-22, the optical film may include a polarizer.

24.21-23, a second adhesive film may be further included between the polarizing plate and the first adhesive film.

The present invention provides an adhesive film having a high refractive index and variable adhesive force by UV irradiation.

The present invention provides an adhesive film that has a high refractive index and whose adhesion to the base film is significantly reduced by UV irradiation.

The present invention provides an adhesive film that has a high refractive index and whose adhesiveness to the base film is significantly reduced and adhesiveness to the adherend is significantly increased by UV irradiation.

The present invention provides an adhesive film with excellent optical properties and step filling properties.

The present invention provides an adhesive film that provides a thickness reduction effect for an optical display device.

1 is a cross-sectional view of an optical display device according to an embodiment of the present invention.
Figure 2 is a schematic diagram of a manufacturing process of an optical display device according to an embodiment of the present invention.
Figure 3 is a schematic diagram of a process for assembling a display panel and an optical film using a sheet containing a high refractive index adhesive film.

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

In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and the same names are used for identical or similar components throughout the specification. The length and size of each component in the drawings are for illustrative purposes only, and the present invention is not limited to the length and size of each component depicted in the drawings.

In this specification, “upper” and “lower” are defined based on the drawings, and “upper” may be changed to “lower” and “lower” may be changed to “upper” depending on the viewing angle.

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

In this specification, “refractive index” is a value measured in the visible light region, for example, at a wavelength of 380 nm to 780 nm.

In this specification, when describing a numerical range, “X to Y” means more than X and less than Y (X≤ and ≤Y).

The adhesive film of the present invention exhibits a high refractive index of 1.55 or more and at the same time exhibits variable adhesive strength by UV irradiation, thereby improving adhesion to the adherend and improving reliability by increasing the cohesion of the adhesive film by UV irradiation. That is, the adhesive film of the present invention exhibits a high refractive index and has a significantly high rate of decrease in adhesive force to the base film due to UV irradiation. Therefore, when the laminate of the adhesive film and the base film of the present invention is laminated on an adherend and then irradiated with UV light, the base film can be easily separated from the adhesive film. This can provide the effect of reducing the thickness of the optical display device. The adhesive film of the present invention exhibits a high refractive index and increases the adhesion to the adherend by UV irradiation, while the adhesion to the base film is significantly lowered, so that the base film can be easily removed and reliability after lamination to the adherend is improved, and optical It is possible to realize a thinner display device. In the above refractive index range, even if it is laminated on a high refractive index adherend, light extraction efficiency can be increased by minimizing reflection of light incident from the adherend to the adhesive film.

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

The adhesive film according to this example has an adhesive force change rate of 90% or more according to the following formula 1:

[Equation 1]

Adhesion change rate = [(A-B)/A] x 100

(In Equation 1 above,

A is the adhesive force (unit: gf/inch) when peeling the base film from the adhesive film after laminating the laminate of the adhesive film and base film on a glass plate.

B is the adhesive force (unit: gf/inch) when the laminate of the adhesive film and the base film is laminated on a glass plate, irradiated with UV, and then the base film is peeled from the adhesive film.

The “glass plate” may be an alkali-free glass plate.

Within the range of the above adhesion change rate, the production of the adhesive film and the base film is facilitated, and when the laminate of the adhesive film and the base film is laminated on the adherend, the base film is easily separated from the adhesive film only by UV irradiation, thereby forming the adherend. It is possible to increase the adhesion with and realize a thinner optical display device.

Preferably, the rate of change in adhesion in Equation 1 may be 90% to 99%, more preferably 90% to 98%.

The base film may be a film used in manufacturing the adhesive film. The base film ensures the appearance of the adhesive film when applying the adhesive composition, but must be easily removed after the adhesive film is adhered to the adherend.

The base film is a polymer film that has not been release treated. For example, the base film may be a polyester-based film that has not been release treated, including a polyethylene terephthalate (PET)-based film, etc., or a triacetyl film that has not been release treated. It may include cellulose ester-based films including cellulose (TAC) films, cycloolefin polymer (COP) films, and acrylic-based films. The “mold release treatment” is a typical release treatment known to those skilled in the art and may include, for example, one or more of silicon and fluorine treatments. If a release-treated film is used as the base film, the adhesive film may have poor appearance.

In one embodiment, the base film may have a high UV light transmittance in order to achieve the effect of varying the adhesive force by UV irradiation to the adhesive film during the UV irradiation process. For example, the base film may have a light transmittance of 70% or more, for example, 70% to 100%, in the UV irradiation range of 250 nm to 400 nm. Within the above range, the adhesive strength of the adhesive film of the present invention may be lowered by UV irradiation.

UV irradiation is to irradiate UV from the side of the base film to a specimen in which a base film, an adhesive film, and a glass plate are sequentially laminated. UV irradiation is 1000 mJ/cm ² or less at a wavelength of 250 nm to 400 nm, for example, 50 mJ/cm ² to 800 mJ/. It can be performed at an intensity of cm ² . UV irradiation may be performed using, but is not limited to, an LED lamp, high-pressure mercury lamp, metal halide lamp, etc.

Adhesion is a value measured at 25°C.

In Equation 1, A may be 1000 gf/inch or more, for example, 1000 gf/inch to 3000 gf/inch. Within the above range, the adhesive film can be fixed to the base film, making it easy to manufacture a laminate of the adhesive film and the base film, and also making it easy to secure adhesion to the adherend. A laminate of an adhesive film and a base film can be manufactured by coating an adhesive composition on one surface of a base film to form a coating layer, then drying and curing (aging) the coating layer. This is explained in detail below.

In Equation 1, B may be 100 gf/inch or less, for example, 10 gf/inch to 100 gf/inch. Within the above range, removal of the base film from the adhesive film may be easy.

The adhesive film may have an adhesive force to the adherend of 200 gf/inch or more, for example, 300 gf/inch to 2500 gf/inch. Within the above range, lamination of additional adherends can be facilitated by being well fixed to the adherend.

In this specification, “adherent” may include one or more of inorganic materials, including glass, organic materials, and mixtures of organic materials and inorganic materials. The 'adherent' may be in the form of a plate, sheet, film, or display panel (touch panel layer). A pattern may be formed on the ‘adhered body’. The 'adherent' may have a refractive index of 1.5 or more.

The adhesive film has a refractive index of 1.55 or higher. Within the above range, when laminated on an adherend with a high refractive index of 1.5 or higher, reflection of light incident from the adherend can be reduced to increase light extraction efficiency. For example, the adhesive film may have a refractive index of 1.55 to 1.8 or 1.60 to 1.7.

The adhesion of an adhesive film to an adherend can be increased by UV irradiation.

In one embodiment, the adhesive film may have an adhesion change rate of 10% or more, for example, 20% to 1000%, 10% to 500%, or more for example, 20% to 100% of the formula 2 below:

[Equation 2]

Adhesion change rate = [(D - C)/C] x 100

(In Equation 2 above, C is the adhesive force of the adhesive film to the glass plate (unit: gf/inch) measured by laminating a laminate of a base film and an adhesive film on a glass plate,

D is the adhesive force of the adhesive film to the glass plate (unit: gf/inch) after the laminate of the base film and the adhesive film was laminated on a glass plate and irradiated with UV.

The “glass plate” may be an alkali-free glass plate.

Within the range of the adhesive force change rate, the adhesive film is more strongly fixed to the adherend, for example, a glass plate, by UV irradiation, thereby facilitating the stacking of additional adherends and allowing the adhesive film to easily function as an interlayer adhesive film.

UV irradiation may be performed at a wavelength of 250 nm to 400 nm and at an intensity of 1000 mJ/cm ² or less, for example 50 mJ/cm ² to 800 mJ/cm ² . UV irradiation may be performed using, but is not limited to, an LED lamp, high-pressure mercury lamp, metal halide lamp, etc.

UV irradiation includes irradiating UV from the adhesive film side to a laminate of an adhesive film and a glass plate, or irradiating UV from the base film side to a laminate of a base film, an adhesive film, and a glass plate.

Adhesion is the value measured at 25°C.

In Equation 2, C may be 500 gf/inch or more, for example, 500 gf/inch to 2000 gf/inch. Within the above range, lamination of additional adherends can be facilitated by being well fixed to the adherend.

In Equation 2, D may be 600 gf/inch or more, for example, 600 gf/inch to 3000 gf/inch. In the above range, the adhesive film can be more strongly fixed to the adherend, for example, a glass plate, by UV irradiation, thereby facilitating the lamination of additional adherends and allowing the adhesive film to easily function as an interlayer adhesive film.

In particular, in the adhesive film of the present invention, when a laminate of a base film and an adhesive film is adhered to an adherend and then irradiated with UV, the adhesion to the base film is significantly lowered and at the same time the adhesion to the adherend is increased, thereby avoiding the adhesive film. By making it very easy to remove the base film along with fixing the complex, adhesion to the adherend and fairness can be achieved at the same time.

The adhesive film may have a haze of 1% or less, for example, 0% to 0.5%, in the visible light region, for example, at a wavelength of 550 nm. Within the above range, light extraction efficiency can be increased by transmitting light incident from the adherend.

The adhesive film may have a thickness of 25 μm or less, for example, greater than 0 μm and less than or equal to 25 μm, or 1 μm to 25 μm. Within the above range, it can be used in optical display devices.

The adhesive film may have a glass transition temperature of -50°C to 15°C, specifically -40°C to 10°C, and more specifically -30°C to 5°C. Within the above range, there may be an effect of providing excellent wettability to the adherend and excellent step embedding.

The adhesive film includes a (meth)acrylic binder, a photoreactive monomer, and a photoinitiator.

(Meth)acrylic binders contain aromatic groups and hydroxyl groups and can increase the adhesion and refractive index of the adhesive film.

The (meth)acrylic binder may have a weight average molecular weight of 200,000 to 3 million, specifically 400,000 to 2 million. Within the above range, the reliability of the adhesive film may be stable.

The (meth)acrylic binder may include a (meth)acrylic copolymer of a monomer mixture including an aromatic group-containing (meth)acrylic monomer and a hydroxyl group-containing (meth)acrylic monomer.

An aromatic group-containing (meth)acrylic monomer can increase the refractive index of the adhesive film. The aromatic group-containing (meth)acrylic monomer may include (meth)acrylate having one or more aromatic groups, but preferably may include one or more types of (meth)acrylate having two or more aromatic groups. Containing two or more aromatic groups in the aromatic group-containing (meth)acrylate can help the adhesive film secure a high refractive index. In addition, by containing two or more aromatic groups in the aromatic-containing (meth)acrylate, the dispersibility of the inorganic particles can be increased when the inorganic particles described in detail below are included.

In one embodiment, the aromatic group-containing (meth)acrylic monomer is a monomer whose homopolymer has a refractive index of 1.55 or more, for example, 1.55 to 1.80, and may include, for example, a (meth)acrylic monomer of the following formula (1):

[Formula 1]

CH ₂ =C(R ¹ )-C(=O)-O-(R ² )n-Ar

(In Formula 1 above,

R ¹ is hydrogen or methyl group,

R ² is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms or a substituted or unsubstituted alkyleneoxy group having 1 to 10 carbon atoms,

Ar is a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms,

n is an integer from 0 to 3).

Preferably, the aromatic group-containing (meth)acrylic monomer may include a (meth)acrylic monomer having two or more substituted or unsubstituted aromatic groups. A (meth)acrylic monomer having two or more substituted or unsubstituted aromatic groups can facilitate securing the refractive index of an adhesive film when combined with the above-mentioned inorganic particles. The aromatic group may be a monocyclic ring or a heterocyclic ring.

Preferably, Ar in Formula 1 may be substituted with an aryl group having 6 to 10 carbon atoms or an aryloxy group having 6 to 10 carbon atoms.

Preferably, in Formula 1, R ² is a hydroxyl group, an amino group, an alkyl group with 1 to 20 carbon atoms, an aryl group with 6 to 20 carbon atoms, an aryl alkyl group with 7 to 10 carbon atoms, a halogen, a cycloalkyl group with 3 to 10 carbon atoms, a cyano group, It may be substituted with a thiol group, etc.

In one embodiment, the aromatic group-containing (meth)acrylic monomer is a monomer of Formula 1 in which Ar is substituted with an aryl group having 6 to 10 carbon atoms and Ar is substituted with an aryloxy group having 6 to 10 carbon atoms. It may contain a mixture of monomers. In this case, it may be easy to implement the effect of the present invention.

For example, aromatic group-containing (meth)acrylic monomers include phenoxybenzyl (meth)acrylate, phenylphenoxyethyl (meth)acrylate, naphthyl (meth)acrylate, biphenylmethyl (meth)acrylate, and biphenylmethyl (meth)acrylate. It may contain one or more types, preferably two or more types of phenylyl (meth)acrylate.

The aromatic group-containing (meth)acrylic monomer is 30% to 95% by weight, specifically 40% to 90% by weight, more specifically 50% to 90% by weight, in the monomer mixture for the (meth)acrylic copolymer. may be included. Within the above range, it can help increase the refractive index of the adhesive film.

Hydroxyl group-containing (meth)acrylic monomers can provide adhesion to the adhesive film. The hydroxyl group-containing (meth)acrylic monomer may include one or more types of (meth)acrylates having 1 to 10 carbon atoms containing one or more hydroxyl groups. 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 be included in the monomer mixture for the (meth)acrylic copolymer in an amount of 5% to 70% by weight, specifically 5% to 30% by weight, and more specifically 10% to 30% by weight. there is. Within the above range, the effect of securing stability and increasing adhesive strength at high temperature and/or high humidity reliability of the adhesive film can be provided.

The monomer mixture may further include one or more of a (meth)acrylic monomer having an amide group and a (meth)acrylic monomer having an alkyl group.

A (meth)acrylic monomer having an amide group is advantageous for particle dispersion in an adhesive film and can provide the function of improving the haze of the film. (meth)acrylic monomers having an amide group include (meth)acryl amide, octadecyl (meth)acryl amide, isopropyl (meth)acrylamide, aminopropyl (meth)acrylamide, diethylaminopropyl (meth)acryl amide, and dimethyl. It may include one or more of aminopropyl (meth)acryl amide and N,N-diethyl (meth)acryl amide.

The (meth)acrylic monomer having an amide group may be included in the monomer mixture in an amount of 0% to 20% by weight, specifically 0% to 10% by weight, and 0.1% to 10% by weight. Within the above range, the effect of increasing the adhesive strength of the adhesive film can be provided.

The (meth)acrylic monomer having an alkyl group may include a (meth)acrylic acid ester having a straight or branched alkyl group having 1 to 20 carbon atoms (preferably 2 to 20 carbon atoms). (meth)acrylic acid esters having an alkyl group having 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and iso-butyl (meth)acrylate. ) Acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, iso-octyl (meth)acrylate , nonyl (meth)acrylate, decyl (meth)acrylate, and dodecyl (meth)acrylate, but is not limited thereto.

The (meth)acrylic monomer having an alkyl group may be included in the monomer mixture in an amount of 0% to 40% by weight, specifically 0% to 30% by weight, and 0.1% to 10% by weight. Within the above range, the effect of increasing the adhesive strength of the adhesive film can be provided.

The photoreactive monomer is photocured by UV irradiation and a photoinitiator while the cured product of the (meth)acrylic binder provides adhesion, thereby lowering the adhesion of the adhesive film to the base film and increasing the adhesion to the adherend, such as a glass plate. It can be raised.

The photoreactive monomer may include a bifunctional or higher (meth)acrylate having two or more UV curable photoreactive functional groups.

Bifunctional or higher (meth)acrylates undergo a photocuring reaction with a photoinitiator when the adhesive film is irradiated with UV light, thereby increasing the degree of cross-linking of the adhesive film, thereby lowering the adhesion to the base film and increasing the adhesion to the adherend. Bifunctional or higher (meth)acrylate has a faster photocuring reaction even at a lower content compared to monofunctional (meth)acrylate, making it easier to reduce adhesion.

The difunctional or higher (meth)acrylate may specifically include difunctional to ten-functional, and more specifically, bi- to hexa-functional (meth)acrylate. For example, bifunctional or higher (meth)acrylates include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and 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 ) Acrylate, di(meth)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 difunctional acrylates such as 9,9-bis[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 hexafunctional urethane (meth)acrylate (ex. isocyanate monomer and trimethylolpropane tri(meth) One or more types of hexafunctional acrylates, such as acrylate reactants, may be included, but are not limited thereto.

The photoreactive monomer may be included in the adhesive film in an amount of 1% to 50% by weight, specifically 1% to 30% by weight, and more specifically 1% to 10% by weight. Within the above range, the adhesive strength of the adhesive film may not be affected before UV irradiation and the adhesive strength of the adhesive film may be lowered after UV irradiation.

The photo initiator may include a photo radical initiator that generates photo radicals by light such as UV.

In one embodiment, the photoinitiator may include a long-wavelength absorbing photoinitiator having a maximum absorption wavelength of 250nm or more, for example, 300nm to 400nm. When UV is irradiated through the base film in the above maximum absorption wavelength range, a significant reduction in adhesion due to UV irradiation can be obtained, so the effect of the present invention can be obtained even with low intensity UV irradiation. The “maximum absorption wavelength” refers to the wavelength at which the maximum absorbance occurs when the photoinitiator is dissolved in cyclohexane at a concentration of 1 mg/ml and then the absorbance is measured.

The photoinitiator may specifically be a phosphine oxide-based, benzoin-based, hydroxy ketone-based, or aminoketone-based photoinitiator. For example, photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-2-phenylacetophenone. , 2,2'-diethoxy acetophenone, 2,2'-dibutoxy acetophenone, 2-hydroxy-2-methyl propiophenone, p-t-butyl trichloro acetophenone, p-t-butyl dichloro acetophenone, 4- Acetophenone compounds such as chloroacetophenone, 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-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-( Hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4 noncydiethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthra Quinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Acetophenone dimethyl ketal, p-dimethylamino benzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and 2,4,6-trimethylbenzoyl-di. Phenyl-phosphine oxide, etc. may be mentioned, but it is not limited to these.

The photoinitiator may be included in the adhesive film in an amount of 0.01% to 5% by weight, specifically 0.05% to 4% by weight, and more specifically 0.1% to 1% by weight. Within the above range, the adhesive strength of the adhesive film is not affected before UV irradiation, and the adhesive strength of the adhesive film can be lowered after UV irradiation, and the optical transparency of the adhesive film can be prevented from being lowered due to the remaining amount of photoinitiator.

The adhesive film may further include a crosslinking agent.

The crosslinking agent can heat-cure the (meth)acrylic binder to form the matrix of the adhesive film and increase the reliability of the adhesive film.

The crosslinking agent may include a conventional thermal curing agent used to thermally cure the (meth)acrylic binder. For example, the crosslinking agent may include one or more of an isocyanate-based crosslinking agent, a carbodiimide-based crosslinking agent, an aziridine-based crosslinking agent, and an epoxy-based crosslinking agent. Preferably, an isocyanate-based crosslinking agent may be included as a crosslinking agent.

The isocyanate-based crosslinking agent may include an isocyanate-type crosslinking agent having two or more functions, for example, two to six functions. In one embodiment, the isocyanate-based crosslinking agent is xylene diisocyanate (XDI) including m-xylene diisocyanate, methylene bis(phenylisocyanate) (MDI) including 4,4'-methylenebis(phenylisocyanate), and the like. It may include one or more of naphthalene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, or adducts thereof, or isocyanurate forms thereof. For example, the above adduct or isocyanurate form includes trimethylolpropane adduct of tolylene diisocyanate, trimethylolpropane adduct of hexamethylene diisocyanate, trimethylolpropane adduct of isophorone diisocyanate, and xylene diisocyanate. It may be a trimethylolpropane adduct, an isocyanurate form of tolylene diisocyanate, an isocyanurate form of hexamethylene diisocyanate, or an isocyanurate form of isophorone diisocyanate.

The crosslinking agent may be included in an amount of 0.001 to 5 parts by weight, specifically 0.005 to 3 parts by weight, based on 100 parts by weight of the (meth)acrylic binder. Within the above range, the matrix of the adhesive film can be well formed and adhesive strength can be achieved.

The adhesive film may further include a silane coupling agent.

Silane coupling agents can further increase the peeling power of the adhesive film from the adherend. Silane coupling agents may include common types known to those skilled in the art. For example, silane coupling agents have epoxy structures such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. a silicon compound having; Silicon compounds containing polymerizable unsaturated groups such as vinyl trimethoxysilane, vinyltriethoxysilane, and (meth)acryloxypropyltrimethoxysilane; Amino group-containing silicon compounds such as 3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane ; and 3-chloropropyl trimethoxysilane, etc., but is not limited thereto.

The silane coupling agent may be included in the adhesive film at 0.001% to 2% by weight, specifically 0.001% to 1% by weight. Within the above range, the adhesion of the adhesive film to the adherend can be increased without affecting other physical properties of the adhesive film.

The adhesive film may further include inorganic particles.

Inorganic particles can be included in the adhesive film to help reduce adhesion due to UV irradiation.

The inorganic particles are not limited in shape, and may be, for example, spherical, amorphous, plate-shaped, or granular. The inorganic particles have an average particle diameter (D50) smaller than the thickness of the adhesive film, and as nanoparticles, they may be 1 nm to 200 nm, for example, 5 nm to 150 nm. Within the above range, it can be included in the adhesive film and can achieve the effect of the adhesive film. The “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.

The inorganic particles may include inorganic particles that have not been surface-treated, but by including surface-treated inorganic particles, the inorganic particles can be well dispersed in the adhesive composition, thereby preventing an increase in haze of the adhesive film. Surface treatment can be performed by conventional methods known to those skilled in the art. For example, inorganic particles may be surface treated with a (meth)acrylic compound or the like.

In one embodiment, the inorganic particles may include inorganic particles with a refractive index of 1.5 or more, for example, 1.5 to 1.8. By helping to increase the refractive index of the adhesive film within the above range, light extraction efficiency can be increased by reducing reflection of light incident from the adherend when laminated on the adherend. For example, the inorganic particles may include one or more of zirconia, titania, zinc oxide, and aluminum oxide, preferably zirconia.

The inorganic particles may be included in the adhesive film at 0% to 80% by weight, specifically 5% to 80% by weight, more specifically 5% to 70% by weight, and most specifically 25% to 70% by weight. Within the above range, the refractive index of the adhesive film can be increased without affecting the adhesive strength of the adhesive film before and after UV irradiation.

The adhesive film may further include a UV absorber.

The UV absorber can prevent damage to the light-emitting elements in the light-emitting display panel laminated on the lower surface of the adherend by absorbing UV incident from the outside, thereby extending the lifespan of the light-emitting elements. In one embodiment, the adhesive film containing a UV absorber may have a light transmittance of 70% or less, for example, 30% to 70%, at a wavelength of 390 nm or less, for example, a wavelength of 380 nm to 390 nm. Within the above range, damage to the light emitting device can be prevented.

In one embodiment, the UV absorber may have a maximum absorption wavelength of 370 nm to 410 nm, specifically 370 nm to 400 nm. Within the above range, damage to the light emitting device can be prevented and the adhesive strength of the adhesive film may not be reduced due to UV irradiation.

In one embodiment, the UV absorber may be an indole-based UV absorber, but is not limited thereto.

The UV absorber may be included in an amount of 0.01% to 2% by weight, specifically 0.01% to 1% by weight, in the adhesive film. Within the above range, the function of preventing damage to the light emitting device can be implemented without affecting the decrease in adhesive strength caused by UV irradiation of the adhesive film.

The adhesive film may further include additives.

Additives include antistatic agents, surfactants, curing accelerators, ionic liquids, lithium salts, softeners, molecular weight regulators, antioxidants, anti-aging agents, stabilizers, tackifier resins, modified resins (polyol resins, phenol resins, acrylic resins, polyester resins). , polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, antifoaming agent, plasticizer, dye, pigment (coloring pigment, extender pigment, etc.), processing agent, fluorescent whitening agent, dispersing agent, heat stabilizer, light stabilizer, It may include, but is not limited to, conventional additives such as coagulants and lubricants.

The additive may be included in 10% by weight of the adhesive film, specifically 0.01% to 10% by weight, and specifically 0.01% to 1% by weight. Within the above range, the additive effect can be achieved without affecting the adhesion and reliability of the adhesive film.

The adhesive film can be manufactured by coating the adhesive composition described in detail below on one surface of the base film to form a coating layer, and then drying and curing (or aging) the coating layer. A release film may be additionally laminated to one side of the coating layer or adhesive film to prevent foreign substances from sticking to the adhesive film after or before curing the coating layer. The base film is as described above. The release film is a polymer film that has been subjected to release treatment (e.g., silicone treatment or fluorine treatment) and may include a polyester film including a polyethylene terephthalate film.

Drying may include, but is not limited to, treating the coating layer at 100°C to 150°C for 0.5 minutes to 5 minutes. Curing (or aging) may include, but is not limited to, treating the dried coating layer at 40°C to 80°C for 0.5 to 3 days.

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

The adhesive composition includes a (meth)acrylic binder, a photoreactive monomer, and a photoinitiator. The adhesive composition may further include one or more of a crosslinking agent and inorganic particles. The adhesive composition may further include one or more of a silane coupling agent and a UV absorber. The adhesive composition may further include additives.

The (meth)acrylic binder, photoreactive monomer, photoinitiator, crosslinking agent, inorganic particles, silane coupling agent, UV absorber, and additives are substantially the same as described above. Accordingly, descriptions of the (meth)acrylic binder, cross-linking agent, photoreactive monomer, photoinitiator, inorganic particle, silane coupling agent, UV absorber, and additive are omitted here.

The photoreactive monomer is present in an amount of 0.1 to 50 parts by weight, specifically 1 to 30 parts by weight, and 1 to 20 parts by weight, based on 100 parts by weight of the (meth)acrylic binder or the total of the (meth)acrylic binder and the inorganic particles. , may be included in 5 to 15 parts by weight. Within the above range, there may be an effect of lowering the adhesion to the base film after UV irradiation.

The photoinitiator may be included in an amount of 0.001 to 5 parts by weight, specifically 0.1 to 1 part by weight, based on 100 parts by weight of the (meth)acrylic binder or the total of the (meth)acrylic binder and the inorganic particles. Within the above range, there may be an effect of lowering the adhesion to the base film after UV irradiation.

The crosslinking agent may be included in an amount of 0.001 parts by weight to 5 parts by weight, specifically 0.005 parts by weight to 3 parts by weight, based on 100 parts by weight of the (meth)acrylic binder or the total of the (meth)acrylic binder and the inorganic particles. Within the above range, there may be an effect of increasing the cohesion of the adhesive film.

The (meth)acrylic binder may be included in an amount of 30 to 95 parts by weight, specifically 40 to 95 parts by weight, based on 100 parts by weight of the total of the (meth)acrylic binder and the inorganic particles. Within the above range, there may be an effect of serving as a matrix in which inorganic particles can be well dispersed.

The inorganic particles may be included in an amount of 5 to 70 parts by weight, specifically 5 to 60 parts by weight, based on a total of 100 parts by weight of the (meth)acrylic binder and the inorganic particles. Within the above range, there may be an effect of increasing the refractive index of the adhesive film.

The adhesive composition may further include a solvent. The solvent can increase the applicability of the adhesive composition so that the adhesive composition is uniformly applied. The solvent may include one or more organic solvents commonly known to those skilled in the art.

Hereinafter, an optical member according to an embodiment of the present invention will be described.

The optical member according to this embodiment includes the adhesive film of the present invention.

In one embodiment, the optical member includes an adhesive film and an adherend laminated on at least one surface of the adhesive film. In one embodiment, the adherend may have a higher refractive index compared to the adhesive film. A light emitting device panel is located on the lower surface of the adherend, and light incident from the light emitting device panel can be sequentially transmitted through the adherend and the adhesive film. The adhesive film of the present invention can increase light extraction efficiency by lowering the difference in refractive index with the adherend compared to the conventional adhesive film. For example, the adherend may have a refractive index of 1.5 or more, specifically 1.5 to 2.0, and more specifically 1.7 to 2.0.

The optical display device of the present invention includes the adhesive film of the present invention or the optical member of the present invention. The optical display device may include a light emitting display device including an organic light emitting device display device, a liquid crystal display device, etc.

The optical display device includes a display panel including one or more functional layers with a refractive index of 1.5 to 2, a first adhesive film, and an optical film, and the first adhesive film includes the adhesive film of the present invention.

In one embodiment, in an optical display device, a display panel including a functional layer with a refractive index of 1.5 to 2, an adhesive film, and an optical film may be sequentially stacked.

The display panel includes a light emitting element and is a part that emits light to drive the display device. Light-emitting devices among display panels may include, but are not limited to, OLED, QD, QD-OLED, etc.

The functional layer has a refractive index of 1.5 to 2, and can provide additional functions when driving an optical display device or display panel. The functional layer may consist of a single layer or two or more layers.

In one embodiment, the functional layer may include a touch screen panel, a passivation layer, etc. The touch screen panel detects the location of the touch on the screen of the optical display device with a hand or pen, allowing the display device to receive input data from the screen so that it can perform specific processing. The touch screen panel can be made of metal materials such as aluminum and titanium. The passivation layer is an insulating layer and may be composed of multiple layers made of one or more of organic materials and inorganic materials.

Optical films may include window films, windows, polarizers, color filters, retardation films, elliptically polarizing films, reflective polarizing films, anti-reflective films, compensation films, brightness enhancement films, alignment films, light diffusion films, glass shatterproof films, etc. there is. Preferably, the optical film may be a polarizing plate including a polarizer and a protective layer (eg, protective film or protective coating layer) formed on at least one surface of the polarizer.

The above-described base film may not be included between the optical film and the first adhesive film. This is due to the base film being easily removed from the adhesive film by UV irradiation. This is explained in detail in FIG. 2 below.

A second adhesive film may be further included between the optical film and the first adhesive film. The type of the second adhesive film is not limited as long as it can provide high adhesive strength to the optical film. For example, the second adhesive film can be a pressure-sensitive adhesive (PSA).

1 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

Referring to FIG. 1, the optical display device may include a display panel 110, a touch screen panel 120, an adhesive film 140, and an optical film 150 sequentially stacked on the upper surface of the display panel 110. You can. A passivation layer 130 is patterned and formed on the upper surface of the touch screen panel 120. The display panel, touch screen panel, adhesive film, optical film, and passivation layer are each as described in detail above.

Figure 2 is a schematic diagram of a manufacturing process of an optical display device according to an embodiment of the present invention.

Referring to FIG. 2, in (I), a sheet composed of a high refractive index adhesive film 20 and a base film 30 is laminated on a display panel 10 including a high refractive index functional layer. In (II), UV is irradiated from the base film 30 side and then the base film 30 is peeled off. In (III), an adherend 40 including an optical film or the like is laminated on the high refractive index adhesive film 20.

Although not shown in FIG. 2, an additional adhesive film may be additionally included between the high refractive index adhesive film 20 and the adherend 40.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and should not be construed as limiting the present invention in any way.

Example 1

In the reactor, 90 parts by weight of a mixture of 2-phenoxybenzyl acrylate (PBA-001, Hannong Chemical) and 2-phenylphenoxyethyl acrylate (PP-011, Hannong Chemical) and 10 parts by weight of 4-hydroxybutyl acrylate were added. Add 100 parts by weight of the monomer mixture containing UV initiator and polymerize while purging with nitrogen to obtain (meth)acrylic binder A (weight average molecular weight: 1 million) containing aromatic groups (2-phenoxybenzyl group and 2-phenylphenoxy group) and hydroxyl group. was manufactured.

Zirconia-containing sol (ZP-158, Nippon shokubai, average particle diameter of zirconia (D50): 15 nm, surface treated zirconia, refractive index of zirconia: 1.75) was added to the (meth)acrylic binder A prepared above, and 70 parts by weight of the (meth)acrylic binder prepared above and 30 parts by weight of zirconia were used.

Then, based on solid content, 0.01 parts by weight of a cross-linking agent (L-45, Soken, isocyanate-based cross-linking agent) for a total of 100 parts by weight of 70 parts by weight of the (meth)acrylic binder and 30 parts by weight of zirconia, and Dipenta as a photoreactive monomer. An adhesive composition was prepared by mixing 5 parts by weight of erythritol hexaacrylate and 0.5 parts by weight of a phosphorus initiator (TPO) as a photoinitiator and defoaming.

The prepared adhesive composition was applied to a thickness of 20㎛ to 25㎛ on one side of a polyethylene terephthalate film (TU73A, SKC, thickness: 75㎛, not release treated) as a base film, dried at 120°C for 2 minutes, After curing (aging) for 2 days at 50℃, cover with polyethylene terephthalate film (R56, Toray Co., Ltd., thickness: 38㎛, release treated) as a release film, and cover the base film, adhesive film (thickness: 20㎛), and release film. A laminate was manufactured.

Examples 2 to 6

A laminate of a base film, an adhesive film, and a release film was manufactured in the same manner as in Example 1, except that the content of each component was changed as shown in Table 1 (unit: parts by weight) below. . The UV absorber used in Example 5 was UV-3912 (indole type, Orient Chemical).

Comparative Examples 1 to 2

A laminate of a base film, an adhesive film, and a release film was manufactured in the same manner as in Example 1, except that the content of each component was changed as shown in Table 1 below.

Comparative Example 3

In a reactor, add 100 parts by weight of a monomer mixture containing 50 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of butyl acrylate, and 20 parts by weight of 4-hydroxybutyl acrylate, add a UV initiator, and polymerize while purging with nitrogen to form a (meth)acrylic system. Binder B (weight average molecular weight: 1 million) was prepared.

Then, a laminate of a base film, an adhesive film, and a release film was manufactured in the same manner as in Example 1, except that the content of each component in Example 1 was changed as shown in Table 1 below.

(meth)acrylic binder crosslinking agent zirconia Photoreactive monomer photoinitiator UV absorber type content content content type content content content Example 1 A 70 0.01 30 A 5 0.5 0 Example 2 A 50 0.01 50 A 5 0.5 0 Example 3 A 30 0.01 70 A 5 0.5 0 Example 4 A 50 0.01 50 A 10 0.5 0 Example 5 A 70 0.01 30 A 5 0.5 0.1 Example 6 A 100 0.01 0 A 5 0.5 0 Comparative Example 1 A 100 0.01 0 A 0 0.5 0 Comparative Example 2 A 70 0.01 30 A 5 0 0 Comparative Example 3 B 100 0.01 0 A 5 0.5 0

The physical properties of the laminates prepared in Examples and Comparative Examples were evaluated in Table 2 below, and the results are shown in Table 2 below.

(1) Formula 1 (unit %): After peeling the release film from the laminate of base film/adhesive film/release film (width x height, 2.5 cm x 10 cm) prepared in Examples and Comparative Examples, alkali-free A specimen was prepared by laminating an adhesive film/base film on a glass plate (width x height, 3 cm x 10 cm) using the adhesive film. Adhesive force (A in Equation 1, unit: gf/inch) when the manufactured specimen is fixed to the TA Instrument, an adhesion measurement device, and the base film is peeled from the adhesive film at 25°C, peeling speed of 300 mm/min, and peeling angle of 180°. Measure.

After peeling the release film from the base film/adhesive film/release film laminate (width x height, 2.5cm x 10cm) prepared in the examples and comparative examples, an alkali-free glass plate (width The specimens were produced by laminating them through the adhesive film and then irradiating UV at 500 mJ/cm ² from the base film side with a metal halide lamp. Adhesive force (B in Equation 1, unit: gf/inch) when the manufactured specimen is fixed to the TA Instrument, an adhesion measurement device, and the base film is peeled from the adhesive film at 25°C, peeling speed of 300 mm/min, and peeling angle of 180°. Measure. Calculate the value of Equation 1 above.

(2) Equation 2 (unit: %): After peeling the release film from the laminate of base film/adhesive film/release film (width x height, 2.5 cm x 10 cm) prepared in Examples and Comparative Examples, A specimen was prepared by laminating the adhesive film/base film on an alkaline glass plate (width x height, 3 cm x 10 cm) with the adhesive film as a medium. The manufactured specimen is fixed to the TA Instrument, an adhesion measuring device, and the adhesive film is peeled from the alkali-free glass plate at 25°C, peeling speed of 300 mm/min, and peeling angle of 180°. Adhesion (C in Equation 2, unit: gf/inch) ) is measured.

After peeling the release film from the base film/adhesive film/release film laminate (width x height, 2.5cm x 10cm) prepared in the examples and comparative examples, an alkali-free glass plate (width The specimens were produced by laminating them through the adhesive film and then irradiating UV at 500 mJ/cm ² from the base film side with a metal halide lamp. The manufactured specimen is fixed to the TA Instrument, an adhesion measurement device, and the adhesive film is peeled from the alkali-free glass plate at 25°C, peeling speed of 300 mm/min, and peeling angle of 180°. Adhesion (D in Equation 2, unit: gf/inch) ) is measured. Calculate the value of Equation 2 above.

(3) Refractive index: The base film and release film were separated from the laminate, and only the adhesive film was measured in the visible light region using a refractive index meter Prism coupler.

(4) Haze (unit: %): The base film and release film were separated from the laminate, the obtained adhesive film was laminated to an alkali-free glass plate, and the haze was measured in the visible light range using a haze meter NDH-9000.

(5) Step fillability: A pattern (width x length x height, 25㎛ x 25㎛ x 2㎛) was created on a glass plate with photoresist. The release film was removed from the laminates prepared in Examples and Comparative Examples, and the laminates were laminated on the prepared pattern using an adhesive film and then autoclaved (50°C, 3.5 bar, 1000 seconds). The presence of bubbles in the pattern step portion was confirmed using an optical microscope. If no bubbles were generated at all, it was evaluated as ○, and if any bubbles occurred at all, it was evaluated as x.

(6) Light transmittance (unit: %): Separate the base film and release film from the laminate, laminate the obtained adhesive film on an alkali-free glass plate, and then measure the light transmittance at a wavelength of 390 nm using a UV-spectrometer. was measured.

(7) Tg of adhesive film (unit: ℃): The base film and release film were separated from the laminates prepared in the examples and comparative examples, and the obtained adhesive film was measured by DSC.

base film glass plate refractive index Haze Step fillability light transmittance Tg A B Equation 1 C D Equation 2 Example 1 1400 90 93.6 1200 1500 25 1.57 0.3 ○ 90.8 -10 Example 2 1200 70 94.2 1000 1300 30 1.62 0.5 ○ 90.7 -5 Example 3 1000 60 94 800 1200 50 1.65 0.4 ○ 90.8 -5 Example 4 1200 40 96.7 1000 1300 30 1.62 0.5 ○ 90.5 0 Example 5 1400 90 93.6 1200 1500 25 1.57 0.3 ○ 65.0 -10 Example 6 1700 95 94.4 1500 1800 20 1.55 0.4 ○ 90.6 -20 Comparative Example 1 1700 1600 5.9 1500 1500 0 1.55 0.3 ○ 90.7 -20 Comparative Example 2 1400 1300 7.1 1200 1200 0 1.57 0.4 ○ 90.6 -20 Comparative Example 3 1800 90 95 1700 2000 17.6 1.48 0.4 ○ 90.5 -43

As shown in Table 2, the adhesion of the adhesive film of the present invention to the base film is significantly reduced by UV irradiation, so that the formula 1 of the present invention is more than 90%, and the adhesion to the base film is significantly reduced by UV irradiation. The adhesion to the adherend was significantly increased, resulting in excellent processability, high refractive index, excellent optical properties, and step filling ability.

On the other hand, the adhesive film of the comparative example did not have the effect 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 (24)

An adhesive film containing a (meth)acrylic binder, a photoreactive monomer, a photoinitiator, and a thermosetting crosslinking agent,
The adhesive film has an adhesive force change rate of 90% or more according to the following formula 1, and the adhesive film has a refractive index of 1.55 or more:
[Equation 1]
Adhesion change rate = [(A - B)/A] x 100
(In Equation 1 above, A is the adhesive force (unit: gf/inch) when peeling the base film from the adhesive film after laminating the laminate of the adhesive film and the base film on a glass plate.
B is the adhesive force (unit: gf/inch) when the laminate of the adhesive film and the base film is laminated on a glass plate, irradiated with UV, and then the base film is peeled from the adhesive film.
The adhesive film of claim 1, wherein in Equation 1, A is 1000 gf/inch or more, and in Equation 1, B is 100 gf/inch or less.
The adhesive film of claim 1, wherein the adhesive film has an adhesive force change rate of 10% or more according to the following formula 2:
[Equation 2]
Adhesion change rate = [(D - C)/C] x 100
(In Equation 2 above, C is the adhesive force of the adhesive film to the glass plate (unit: gf/inch) measured by laminating a laminate of a base film and an adhesive film on a glass plate,
D is the adhesion of the adhesive film to the glass plate after laminating the laminate of the base film and the adhesive film on the adherend and irradiating it with UV (unit: gf/inch)).
The adhesive film of claim 3, wherein in Equation 2, C is 500 gf/inch or more, and in Equation 2, D is 600 gf/inch or more.
The method of claim 1, wherein the (meth)acrylic binder is a (meth)acrylic copolymer of a monomer mixture including an aromatic group-containing (meth)acrylic monomer, a hydroxyl group-containing (meth)acrylic monomer, and an alkyl group-containing (meth)acrylic monomer. Containing an adhesive film.
The method of claim 1, wherein the (meth)acrylic binder includes a (meth)acrylic copolymer of a monomer mixture,
In the monomer mixture, the aromatic group-containing (meth)acrylic monomer is 30% to 95% by weight, the hydroxyl group-containing (meth)acrylic monomer is 5% to 70% by weight, and the alkyl group-containing (meth)acrylic monomer is 0% to 95% by weight. An adhesive film of 40% by weight.
The adhesive film of claim 1, wherein the photoinitiator is included in an amount of 0.1% to 5% by weight of the adhesive film.
The adhesive film of claim 1, wherein the adhesive film further includes inorganic particles.
The adhesive film of claim 8, wherein the inorganic particles include inorganic particles with a refractive index of 1.5 or more.
The adhesive film of claim 8, wherein the inorganic particles include zirconia.
The adhesive film according to claim 8, wherein the inorganic particles are contained in an amount of 5% to 80% by weight in the adhesive film.
The adhesive film of claim 8, wherein the inorganic particles include surface-treated inorganic particles.
The adhesive film of claim 1, wherein the photoreactive monomer is included in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the (meth)acrylic binder.
The adhesive film of claim 5, wherein the aromatic group-containing (meth)acrylic monomer includes a (meth)acrylic monomer of the following formula (1):
[Formula 1]
CH ₂ =C(R ¹ )-C(=O)-O-(R ² ) _n -Ar
(In Formula 1 above,
R ¹ is hydrogen or methyl group,
R ² is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms or a substituted or unsubstituted alkyleneoxy group having 1 to 10 carbon atoms,
Ar is a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms,
n is an integer from 0 to 3).
The adhesive film of claim 1, wherein the photo-reactive monomer includes a bifunctional or higher (meth)acrylate.
The method of claim 15, wherein the bifunctional or higher (meth)acrylate 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)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 ) Acrylate, 9,9-bis[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 modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, tris( Meth)acryloxyethyl isocyanurate, diglycerin tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; Dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, 1 of 6 functional urethane (meth)acrylates An adhesive film comprising more than one species.
delete The method of claim 1, wherein the adhesive film further comprises a UV absorber,
The adhesive film has a light transmittance of 70% or less at a wavelength of 390 nm or less.
The adhesive film of claim 1, wherein the adhesive film has a glass transition temperature of -50°C to 15°C.
An optical member comprising the adhesive film of any one of claims 1 to 16, 18, and 19.
A display panel including one or more functional layers having a refractive index of 1.5 to 2;
first adhesive film; and
comprising an optical film,
The first adhesive film is an optical display device comprising the adhesive film of any one of claims 1 to 16, 18, and 19.
The optical display device of claim 21, wherein no base film is included between the optical film and the first adhesive film.
The optical display device of claim 21, wherein the optical film includes a polarizing plate.
The optical display device of claim 23, further comprising a second adhesive film between the polarizer and the first adhesive film.