KR101601338B1 - Adhesive Sheet for optics with no moire and dusts - Google Patents

Abstract

Embodiments of the present invention relate to an optical adhesive film and a display device including the same. The pressure-sensitive adhesive film according to embodiments of the present invention includes a transparent film layer as a substrate, a pressure-sensitive adhesive layer is formed on one surface of the substrate, and a hard coating layer including fine particles is formed on the other surface. ≪ / RTI >

Description

{Adhesive Sheet for optics with no moire and dusts}

Embodiments of the present invention are directed to moire and dust-free optical adhesive films.

The Newton ring (moire phenomenon) refers to a phenomenon in which a convex surface of a convex lens having a large radius of curvature (more than several meters) is placed on a flat glass, and light is irradiated almost vertically from above, , And several concentric circles around the contact point. It was first observed by R. Hook in 1665, but since Newton then measured the radius of the circle precisely, it is called Newton's circle pattern. This is an interference pattern of light due to a thin air layer between the flat glass and the convex surface of the flat convex lens. In normal light, it appears to be colored with a light, but when monochromatic light is irradiated, The pattern is visible, but the contrast is completely opposite in transmitted light. If the glass is perfectly flat, the pattern is also a complete concentric circle. In this case, the radius r of the pattern due to the reflected light is determined by the wavelength? Of the light and the radius of curvature R of the lens, and along the circumference of the radius r satisfying the relation of 2r2 / R =? (2m + The pattern is visible. This phenomenon is based on T. Young's theory of light wave. In the application aspect, it is used to investigate the curvature of a lens or the flatness of a glass. These Newton rings are also called Newton rings. Recently, as the resolution of the display has increased, the touch panel has been suffering from sparkling phenomenon using a particulate-containing film or the appearance of a white dot on the surface of the display screen in order to prevent the phenomenon of new- Clear hard coatings are being used selectively to prevent this. However, when a film for preventing the Newton ring containing the fine particles is used in the touch panel, the sparkling phenomenon occurs on the surface due to the fine particles contained therein, and when the clear hard coating is applied, And has a problem that easily occurs.

An object of the present invention is to provide an optical adhesive film.

Another object to be solved by the embodiments of the present invention is to provide a display device having the optical adhesive film.

Another object to be solved by the embodiments of the present invention is to provide a method of fixing a panel of an optical device to a glass using the optical adhesive film.

Aspects in accordance with one embodiment of the present invention

A transparent film layer;

A hard coating layer comprising a curable resin formed on one surface of the transparent film layer and particles having an average diameter of 1 to 10 mu m; And

And a pressure-sensitive adhesive layer formed on the other surface of the transparent film layer,

And an adhesive force of the hard coating layer to the transparent film layer is 18 kg / cm ² or more.

An aspect according to another embodiment of the present invention relates to a display device comprising the optical adhesive film.

According to another embodiment of the present invention, there is provided a method for manufacturing a pressure-sensitive adhesive optical product, comprising the steps of: adhering a pressure- And adhering the optical adhesive film to a panel of an optical device.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known general functions or configurations will be omitted. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. And the scope of the present invention is not limited by the thickness, size, ratio or the like shown in the drawings.

1 is a schematic cross-sectional view of an optical adhesive film according to an embodiment of the present invention. 1, an optical adhesive film 10 according to an embodiment of the present invention includes a pressure sensitive adhesive layer 14, a transparent film layer 13, and a hard coat layer 12 in sequence. Further, the hard coat layer may be formed from a mixture of the curable resin and the organic or inorganic particles (11).

Also, the adhesion of the hard coating layer to the transparent film layer is preferably 18 kg / cm ² or more. When the thickness is within the above range, dust and Newton ring (moire phenomenon) are not generated due to vibrations that can occur during display device circulation. For example, when a cross-cut tape is adhered to the optical adhesive film of the present invention, it does not come out when peeling off, and no powder after cross-cut is cut off.

The pressure sensitive adhesive layer 14 is brought into contact with the glass, and the hard coating layer is brought into contact with the panel of the optical device by an adhesive.

The optical film according to the embodiments of the present invention can be used, but is not limited to, a case where a panel of an optical device, for example, an LCD, a plasma display panel (PDP)

The transparent film layer 13 serves as a support for supporting the optical adhesive film, and a transparent material such as a glass plate or a plastic film is used. Examples of the plastic film include cellulose resins such as diacetyl cellulose, triacetyl cellulose and acetyl cellulose butyrate; polyolefin resins such as polyethylene resin and polypropylene resin; polyethylene terephthalate resin; polyethylene naphthalate resin; polybutylene terephthalate resin Of various synthetic resins such as polyester resins, polyvinyl chloride resins, polystyrene resins, polyurethane resins, polycarbonate resins, polyamide resins, polyimide resins and fluorine resins. Particularly, , Triacetyl cellulose, and the like. The transparent film layer may be a single layer or a multilayer of two or more layers of the same or different types.

The thickness of the transparent film layer is preferably 5 to 100 mu m. When the thickness is within the above range, the coating layer can be stably supported on the transparent film layer.

The surface of the transparent film layer is preferably subjected to a corona treatment, an atmospheric pressure plasma treatment or a bonding primer treatment so as to enable adhesion.

The hard coating layer 12 located on one side of the transparent film layer can prevent a surface from being scratched due to external factors during the panel manufacturing process of the optical device, and increase the transmittance. In addition, when the air layer between the layer interface and the interface satisfies the interference distance, a Newton ring occurs in which the interference phenomenon appears strongly. However, reflection of the layer interface is minimized and the interference distance is controlled to prevent the occurrence of Newton rings.

In particular, the reflection of the layer interface can minimize the reflection of the interface by controlling the refractive index of the medium. That is, when n _D = 1.5 of the glass on the surface of the optical device and n _D = 1 of the air layer, the coating liquid (including the curable resin (binder) and particles) for forming the hard coating layer having a refractive index similar to that of the air layer is used, The reflectance of 0 can be realized.

In order to avoid a distance at which interference (white light) occurs, for example, particles of about 4 mu m or more can be coated to avoid a white light interference distance to make a gap of 2 mu m or more, thereby avoiding an interference distance, An effect of preventing contact can be realized at the same time.

The hard coating layer may be formed by coating a coating liquid containing a curable resin and particles having an average diameter of 1 to 10 mu m on at least one surface of a transparent film layer by a conventional coating method such as a bar coater, a die coater, a blot coater, A roll coater, a granule coater, spraying, screen printing or the like, followed by curing by drying and irradiation.

The curable resin as the binder component is preferably a raw material capable of being cured by ultraviolet irradiation. For example, urethane acrylate, polyester acrylate, epoxy acrylate, and polyfunctional methacrylate may be used as the acrylic prepolymer. Of these, urethane acrylate and methacrylate are preferably mixed. These acrylic prepolymers can be used singly, but a photopolymerizable monomer can be added to improve crosslinking curability and further improve hardness. Examples of such photopolymerizable monomers include monofunctional acrylic monomers such as 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate , Bifunctional acrylic monomers such as ethylene glycol diacrylate and sterepentyl glycol diacrylate on hydroxypivalic acid, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, trimethylpropane triacrylate and the like Polyfunctional acrylic monomers, etc. may be used singly or in combination of two or more, but not particularly limited thereto.

Examples of the photopolymerization initiator used in the resin that can be cured by irradiation with ultraviolet rays include acetophenones, benzophenones,? -Hydroxyalkylphenones, acylphosphine oxides, thioxanes, benzoins, benzylmethyl ketals, Cyclohexyl phenyl ketone, and the like may be mixed and used, but the present invention is not limited thereto.

The curable resin may be dissolved in a solvent. As the solvent, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and the like may be used singly or in combination of two or more, but not particularly limited thereto.

The particles 11 contained in the hard coating layer may be spherical organic or inorganic particles having an average diameter of 1 to 10 탆 and may be fixed to the transparent film layer 12 by a binder to prevent Newton ring and dust The effect can be improved.

The organic particles may be selected from the group consisting of a polystyrene resin, a styrene-acrylic copolymer resin, an acrylic resin, an amino resin, a divinylbenzene resin, a silicone resin, a urethane resin, a melamine resin, a urea resin, A resin, a xylene-based resin, a polycarbonate-based resin, a polyethylene-based resin, or a polyvinyl chloride-based resin may be used alone or in combination of two or more.

As the inorganic particles, silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like may be used singly or in combination of two or more.

The particles may be included in an amount of 0.05 to 4 parts by weight based on 100 parts by weight of the curable resin. If the content is less than 0.05 part by weight, the effect of preventing the Newton ring phenomenon may not be exhibited. If the content is more than 4 parts by weight, the Newton ring prevention effect may not be obtained, and transparency may be deteriorated.

The thickness of the concavo-convex shape formed by the fine particles is preferably 1 to 5 탆, and the number of the particles per unit area of 1 mm ^{3 of the} hard coat layer may be 150 to 200.

The thickness of the hard coat layer including the concavo-convex shape by the particles may be 1 to 10 mu m, preferably 2 to 5 mu m.

In addition to the curable resin and particles, the hard coat layer may contain other additives such as a resin, a photopolymerization initiator, a photopolymerization accelerator, a lubricant, a fluorescent whitening agent, a pigment, an antistatic agent, a flame retardant, an antibacterial agent, An antioxidant, a plasticizer, a leveling agent, an antifoaming agent, a dispersing agent, a releasing agent, and a crosslinking agent.

In addition, a conventional adhesive layer may be formed on a part or the whole surface of the hard coat layer so as to be adhered to the panel of the optical device.

The surface roughness of the hard coat layer due to the inclusion of fine particles can control the maximum roughness, which may affect the suppression of the Newton ring phenomenon.

Preferably, the hard coat layer has a surface roughness of 100 to 1200 nm, preferably 200 to 800 nm. If it is out of the above range, the anti-Newton effect may not be improved.

Further, the pressure-sensitive adhesive layer 14 is coated on the other surface of the transparent film layer, and the pressure-sensitive adhesive layer is a pressure-sensitive pressure-sensitive adhesive layer between the panel and the glass of the optical device, and has a storage modulus of 10 ⁴ to 10 ⁶ Pa , The shear strength at 80 ° C may be at least 15 kg / in ² . If the value is less than the above value, there is a high possibility that the rework workability durability is reduced or the residue is left.

The pressure-sensitive adhesive layer may be acrylic, silicone, rubber, polyester, urethane or the like, and is not particularly limited as long as it has transparency that does not impair the visibility of the display device. Preferably, an acrylic polymer adhesive having a molecular weight of 800,000 to 170,000 is preferred.

The pressure-sensitive adhesive layer may be prepared by a conventional method for producing a pressure-sensitive adhesive layer, as required.

The thickness of the pressure-sensitive adhesive layer may be 5 to 75 占 퐉, preferably 15 to 35 占 퐉. When the thickness of the pressure-sensitive adhesive layer is less than 5 m, there is a risk of deterioration of adhesion due to wetting deterioration when adhering to a hard substrate. When the thickness exceeds 75 m, the probability of inflow of foreign substances such as air bubbles and gel in the pressure- .

Further, the thickness of the optical adhesive film of the present invention comprising the pressure-sensitive adhesive layer, the transparent film layer and the hard coating layer may be 30 to 150 탆, preferably 60 to 80 탆. When the thickness of the optical adhesive film is less than 30 탆, the handling of the optical adhesive film is difficult due to the thin film thickness of the substrate and plywood, and the air inside the optical adhesive film is not easily released. When the thickness exceeds 150 탆,

The haze of the optical adhesive film of the present invention may be 0.5 to 5%, preferably 0.8 to 2%, more preferably 1.2 to 2%.

The light transmittance of the optical adhesive film of the present invention may preferably be 90% or more.

Another embodiment of the present invention relates to a display device having the optical adhesive film. 2 is a schematic cross-sectional view of a display device 100 according to another embodiment of the present invention. Referring to FIG. 2, a display device according to embodiments of the present invention includes a panel 111 of an optical device, The optical adhesive film 120 is bonded to the glass 114 through the adhesive layer 124 to constitute a display panel device.

The panel 111 of the optical device may use a plasma display panel (PDP), an LCD panel, or the like without limitation.

The glass 114 is attached to the uppermost part of the product for the protection of the panel 111 of the optical device and the appearance effect, and is generally made of chemically tempered glass, but is not limited thereto.

In addition, the display device 100 may include a black ink print 113 to provide a frame-free display with an inner print for a visual effect on a frame-less display such as a general borderless TV.

A method for fixing a panel of an optical device to a glass according to embodiments of the present invention includes adhering the pressure sensitive adhesive layer 124 of the pressure sensitive adhesive film 120 to the glass 114, The hard coat layer 121 of the adhesive film may be adhered to the panel 111 of the optical device using a separate adhesive layer 112, but is not limited thereto.

The adhesive film according to embodiments of the present invention can prevent the Newton ring (moire phenomenon) by providing the hard coat layer with a fine particle component to have a surface irregular shape and increase the adhesion between the transparent film layer and the hard coat layer, Dust that can be generated can be prevented.

1 is a schematic cross-sectional view of an optical adhesive film according to an embodiment of the present invention,
2 is a schematic cross-sectional view of a display device according to another embodiment of the present invention,
FIG. 3 is a schematic view illustrating a shear force test of an optical adhesive film according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

Production Example 1 Production of pressure-sensitive adhesive layer

98 parts by weight of ethylhexyl acrylate and 2 parts by weight of hydroxyethyl acrylate were mixed in an ethyl acetate solvent and then a thermal initiator was added and the temperature was raised to 60 ° C to prepare a polymer adhesive resin having a molecular weight of 1,300,000. 1.0 part by weight of a toluene diisocyanate curing agent was mixed with the above-mentioned polymeric pressure-sensitive adhesive resin, and the resulting molded PET was applied to the release PET in consideration of the thickness after drying, and then put into a hot air oven. After drying for 1 minute, aging was carried out at 40 DEG C for 1 day, Thick pressure-sensitive adhesive sheet.

≪ Preparation Example 2 > Preparation of hard coat layer

In order to prepare the hard coating solution, the silica particles having a spherical shape and a diameter of 4 탆 were used. The binder component used was 20 parts by weight of pentaerythritol triacrylate (PETA), and the solvent was methylene isobutyl ketone (MIBK) (or methyl ethyl ketone, MEK) , A hard coating solution containing 0.5 part by weight of the silica particles as 100 parts by weight of a curable resin was coated on a TAC film using Mayer Bar 10 times, dried for 1 minute, and irradiated with ultraviolet rays.

≪ Example 1 > Production of adhesive film

A 25 탆 thick acrylic pressure-sensitive adhesive layer prepared in Preparation Example 1 was transferred on one surface of a 83 탆 -thick transparent film layer having the hard coat layer prepared in Preparation Example 2 by a roll adhesion method to form a pressure-sensitive adhesive layer, A film was produced.

≪ Example 2 >

An adhesive film was prepared in the same manner as in Example 1, except that 2.5 parts by weight of silica beads was added during the hard coating layer formation in Production Example 2. [

≪ Comparative Example 1 &

An adhesive film was produced in the same manner as in Example 1 except that silica beads were not added during the formation of the hard coating layer in Production Example 2.

≪ Comparative Example 2 &

An adhesive film was produced in the same manner as in Example 1, except that the hard coat layer was formed in Production Example 2 and the silica bead content was added in an amount of 5 parts by weight.

<Experimental Example 1> Measurement of physical properties

1) Roughness measurement

The roughness was measured by scanning the surface with CLSM.

2) Haze measurement

The haze of the pressure-sensitive adhesive films prepared in Examples 1 and 2 and Comparative Examples 1 and 2 according to the ASTM D1003 standard test method was measured using a Murakami Hazemeter HM-150 The haze value (%) was measured using a device and is shown in Table 1 below.

3) Moire measurement

The pressure-sensitive adhesive film was squeezed on the glass, and the surface of the pressure-sensitive adhesive film was firmly touched with a hand to check whether or not a Newton ring was produced.

4) Measurement of light transmittance

The light transmittance of the adhesive film was measured with a Shimadzu UV-VIS spectrophotometer UV-3150 instrument.

5) Durability measurement

Change in appearance of the pressure-sensitive adhesive film at high temperature (500 hours at 80 ° C), high temperature and high humidity conditions (60 ° C, 500 hours at 90% humidity), and thermal shock conditions (100 cycles at 30 ° C / 70 ° C for 30 minutes) Was observed with the naked eye.

6) Weatherability measurement

Whether or not the appearance of the pressure-sensitive adhesive film was changed under the conditions of UVA-340, 60e, and 100 hours was visually observed.

&Lt; Experimental Example 2 >

The adhesion test was first performed on the basis of ASTM D3359-02 cross-cut test, and the adhesion between the coating layer and the substrate film was visually determined. The adhesion of the coating layer was determined by observing the surface coating layer at the time when the aluminum bar was peeled off after the experiment of Example 3 described later.

&Lt; Experimental Example 3 > Shear force test of the pressure-sensitive adhesive layer

The shear force of the pressure-sensitive adhesive layer was measured after lamination of the optical film prepared above to a glass of the same grade applied to the LCD or PDP.

The optical film was laminated to a glass having a predetermined size as shown in FIG. 3, and then an autoclave (60 ° C, 0.7 bar, 1 hour) was laminated. Then, an AL bar was attached with 1 cm ² using an adhesive, The optical film was peeled off. Thereafter, the force at the time when the film was dropped using a tensioner was measured (tensile speed: 0.1 mm / sec).

As shown in Table 1, from the results of Experimental Examples of the Examples and Comparative Examples, Moire was not observed in the pressure-sensitive adhesive films according to the embodiments of the present invention compared to the pressure-sensitive adhesive films prepared in Comparative Examples, It can be confirmed that it does not inhibit.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be appreciated that embodiments are possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Adhesive film 100: Display device
11, 122: particle 12, 121: hard coat layer
13, 123: transparent film layer 14, 124: pressure-sensitive adhesive layer
111: Panel of optical device 112: Adhesive layer
113: Black ink printing 114: Glass
120: Optical adhesive film

Claims (15)

A transparent film layer;
A hard coating layer comprising a curable resin formed on one surface of the transparent film layer and particles having an average diameter of 1 to 10 mu m; And
And a pressure sensitive adhesive layer formed on the other surface of the transparent film layer, wherein the pressure sensitive adhesive layer has a storage modulus of 10 ⁴ to 10 ⁶ Pa at 25 ° C, a shear strength of not less than 15 kg / in ² at 80 ° C,
Wherein the adhesive force of the hard coat layer to the transparent film layer is 18 kg / cm ² or more.
The method according to claim 1,
Wherein the transparent film layer is made of a material selected from the group consisting of a cellulose resin, a polyolefin resin, a polyester resin, a polyvinyl chloride resin, a polystyrene resin, a polyurethane resin, a polycarbonate resin, a polyamide resin, a polyimide resin, Wherein the adhesive layer is formed of a thermoplastic resin.
The method according to claim 1,
Wherein the curable resin is an ultraviolet curable resin.
The method according to claim 1,
Wherein the particles are organic or inorganic particles.
5. The method of claim 4,
The organic particles may be selected from the group consisting of a polystyrene resin, a styrene-acrylic copolymer resin, an acrylic resin, an amino resin, a divinylbenzene resin, a silicone resin, a urethane resin, a melamine resin, a urea resin, Wherein the adhesive film is at least one selected from the group consisting of a resin, a xylene-based resin, a polycarbonate-based resin, a polyethylene-based resin, and a polyvinyl chloride-based resin.
5. The method of claim 4,
Wherein the inorganic particles are at least one selected from the group consisting of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide and antimony oxide.
The method according to claim 1,
Wherein the particles are contained in an amount of 0.05 to 4 parts by weight based on 100 parts by weight of the curable resin.
The method according to claim 1,
Wherein the hard coating layer has a thickness of 1 to 10 占 퐉.
The method according to claim 1,
Wherein the hard coat layer has a surface roughness of 100 to 1200 nm.
delete The method according to claim 1,
Wherein the pressure-sensitive adhesive layer is at least one selected from the group consisting of an acrylic type, a silicone type, a rubber type, a polyester type and a urethane type pressure-sensitive adhesive.
The method according to claim 1,
Wherein the adhesive film has a haze of 0.5 to 5%.
The method according to claim 1,
Wherein the adhesive film has a light transmittance of 90% or more.
A display device comprising the optical adhesive film according to any one of claims 1 to 9 and 11 to 13.
Bonding an adhesive layer of an optical adhesive film according to any one of claims 1 to 9 and 13 to the glass; And
And adhering the optical adhesive film to a panel of an optical device.

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