KR102403284B1 - Adhesive film and optical member comprising the same - Google Patents

Abstract

An adhesive film formed of a pressure-sensitive adhesive composition comprising a non-hydroxyl group-type (meth)acrylic copolymer, a monofunctional (meth)acrylate, a crosslinking agent, and a silane coupling agent, wherein the adhesive film has a peeling force of 100 gf/25 mm to the polyolefin-based film The above, the pressure-sensitive adhesive film, an optical member including the same, and an optical display device including the same are provided.

Description

Adhesive film, optical member including same, and optical display device including same

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

Recently, a panel for an optical display device is being diversified from a liquid crystal panel to an organic light emitting device panel, a micro light emitting device panel, and the like. The micro light emitting device panel may include a micro light emitting diode having a chip size of about 5 to 100 μm. As the micro light emitting device implements the conventional organic light emitting device in an ultra-small size, it is expected that the application range will be greatly expanded because the LED chip itself can be used as a pixel (pixel) unlike the existing backlight use. In particular, the micro light emitting device can utilize the LED chip itself as a pixel (pixel), so it is suitable for realizing flexible or rollable screens, and is far superior to organic light emitting devices (OLEDs) in terms of color reproducibility, power consumption, and response speed. , the utility value is very high.

On the other hand, since the micro light emitting device is basically a light emitting device like the organic light emitting device, when external moisture or oxygen penetrates, the lifespan or screen visibility may decrease. Accordingly, the micro light emitting device must also be sealed. As a micro light emitting device encapsulation application, a polyolefin-based film that is a film having excellent elastomer properties, for example, a film containing an ethylene vinyl acetate (EVA) copolymer is used. Therefore, in the case of adhering different types of adherends, including the polyolefin-based film used for encapsulation, an adhesive film having excellent adhesion and good reliability in both cases is required.

Background art of the present invention is disclosed in Korean Patent Application Laid-Open No. 2007-0055363.

It is an object of the present invention to provide a pressure-sensitive adhesive film having a high peel force with respect to a polyolefin-based film.

Another object of the present invention is to provide a pressure-sensitive adhesive film having high peel strength for both non-polar films and polar films.

Another object of the present invention is to provide a pressure-sensitive adhesive film having a high peel force for both a hydrophobic film and a hydrophilic film.

Another object of the present invention is to provide an adhesive film having excellent heat resistance reliability and/or wet heat resistance reliability.

The adhesive film of the present invention is formed of a pressure-sensitive adhesive composition comprising a non-hydroxyl group-type (meth)acrylic copolymer, a monofunctional (meth)acrylate, a crosslinking agent and a silane coupling agent, and the adhesive film has a peeling force with respect to the polyolefin-based film It can be more than 100gf/25mm.

The optical member of the present invention may include a polyolefin-based film and the adhesive film of the present invention laminated on at least one surface of the polyolefin-based film.

The optical display device of the present invention may include the adhesive film of the present invention.

The present invention provides a pressure-sensitive adhesive film having a high peel force with respect to a polyolefin-based film.

The present invention provides a pressure-sensitive adhesive film having a high peel force for both a non-polar film and a polar film.

The present invention provides an adhesive film having a high peel force for both a hydrophobic film and a hydrophilic film.

The present invention provides an adhesive film having excellent heat resistance reliability and/or wet heat resistance reliability.

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

It will be described in detail so that a person of ordinary skill in the art can easily carry out the present invention by the following examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

As used herein, “(meth)acryl” may mean acryl and/or methacrylic. As used herein, "copolymer" may include oligomers, polymers, or resins.

In the present specification, "polyolefin-based film" refers to a homopolyolefin-based film such as PE (polyethylene), PP (polypropylene), EVA (ethylene vinyl acetate), or a copolymer of the olefin (eg, 3 of PE, PP and EVA). One copolymer)-based film (SKC, PO2T, EF2V, SG00L).

In the present specification, "peel force" is a value measured at a peeling rate of 300 mm/min and a peeling angle of 180° at 25° C., after the polyolefin-based film, which is an adherend, is pressed with a roll under a load of 2 kg at room temperature and left for 30 minutes after lamination. to be.

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

The adhesive film may have a peel strength of 100 gf/25 mm or more with respect to the polyolefin-based film. In one embodiment, the adhesive film may have a peel strength of 100 gf/25 mm or more for a polyolefin-based film containing an ethylene vinyl acetate homopolymer or an ethylene vinyl acetate copolymer among the polyolefin-based films. Within the above range, the peeling force for the polyolefin-based film encapsulating the microLED is high, and thus the microLED and the polyolefin-based film laminate and the adherend can be prevented from separating and the adhesion reliability can be excellent. For example, the adhesive film may have a peel strength of 100 gf/25 mm to 500 gf/25 mm for a polyolefin-based film, for example, a polyolefin-based film containing an ethylene vinyl acetate homopolymer or ethylene vinyl acetate copolymer.

In one embodiment, the adhesive film may have a peeling force of 500 gf/25 mm or more, for example, 500 gf/25 mm to 1500 gf/25 mm, with respect to a polyester-based film including a polyethylene terephthalate-based film and the like. Within the above range, the laminate of the micro LED and the polyolefin-based film and the polyethylene terephthalate-based film have excellent peel strength to prevent separation between the laminate and the polyethylene terephthalate-based film and have excellent adhesion reliability. As such, the adhesive film of the present invention has excellent peel strength for both films having different polarities (non-polarity and polarity) or different physical properties such as hydrophilicity and hydrophobicity, thereby further increasing the effectiveness of the adhesive film.

The pressure-sensitive adhesive film may have a rate of change of peel force of Equation 1 below 20%. In the above range, the adhesive film has excellent heat resistance reliability, so that the reliability of the micro LED can also be increased when it is adhered to the polyolefin-based film encapsulating the micro LED:

<Equation 1>

Rate of change of peel force = ｜B - A｜/A x 100

(In Equation 1, A is the peel force of the adhesive film to the polyolefin-based film (unit: gf/25 mm),

B is the peeling force of the adhesive film to the polyolefin-based film (unit: gf/25mm) after leaving the laminate of the adhesive film and the polyolefin-based film at 85°C for 120 minutes and leaving it at 25°C for 30 minutes )))

The pressure-sensitive adhesive film may be formed of a pressure-sensitive adhesive composition including a non-hydroxyl group-type (meth)acrylic copolymer, a monofunctional (meth)acrylate, a crosslinking agent, and a silane coupling agent. The "non-hydroxyl group-type (meth)acrylic copolymer" refers to a (meth)acrylic copolymer copolymerized from a (meth)acrylic copolymer that does not contain a hydroxyl group or a monomer mixture that does not contain a (meth)acrylic monomer containing a hydroxyl group. can The inventor of the present invention has found that when the pressure-sensitive adhesive composition of the present invention contains a hydroxyl group-containing (meth)acrylic copolymer instead of a non-hydroxyl group-type (meth)acrylic copolymer, the peeling force for the polyolefin-based film may reach 100 gf/25 mm or more. It was confirmed that no other effects of the present invention could be obtained.

The non-hydroxyl group-type (meth)acrylic copolymer may be cured with a monofunctional (meth)acrylate and a crosslinking agent to form a matrix of the adhesive film, and to implement the above-described peeling force of the adhesive film. The non-hydroxyl group type (meth)acrylic copolymer may have a weight average molecular weight of more than 100,000 and 5 million or less, for example, 600,000 to 3,000,000. Within the above range, the mechanical strength of the pressure-sensitive adhesive film is ensured and the non-hydroxyl group-type (meth)acrylic copolymer in the pressure-sensitive adhesive composition is well spread, thereby achieving an effect of increasing the peeling force of the pressure-sensitive adhesive film.

The non-hydroxyl group-type (meth)acrylic copolymer includes (meth)acrylate having an alkyl group and (meth)acrylate having an alicyclic group, but does not contain a (meth)acrylic monomer having a hydroxyl group or a vinyl monomer having a hydroxyl group However, it may contain copolymers of monomer mixtures.

The (meth)acrylate having an alkyl group is a (meth)acrylic monomer having no alicyclic group, and may include an unsubstituted linear or branched alkyl (meth)acrylic acid ester having 1 to 20 carbon atoms. For example, (meth)acrylate having an alkyl group is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylic Rate, iso-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl ( It may include at least one of meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, and dodecyl (meth) acrylate. Preferably, it has a branched alkyl group having 4 to 8 carbon atoms. By using (meth)acrylate, there may be further an effect of increasing the initial peeling force.

The (meth)acrylate having an alicyclic group may include a (meth)acrylic monomer having an alicyclic group having 3 to 10 carbon atoms. For example, the (meth)acrylate having an alicyclic group is at least one of cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, bornyl (meth)acrylate, and isobornyl (meth)acrylate. may include Preferably, a (meth)acrylic monomer having an alicyclic group having 7 to 10 carbon atoms, more preferably isobornyl (meth)acrylate can be used.

In one embodiment, the monomer mixture may consist of only (meth)acrylate having an alkyl group and (meth)acrylate having an alicyclic group. In this case, while ensuring the peeling force for the polyolefin-based film of the present invention, there may be an effect of excellent durability and improved adhesion. The monomer mixture contains 90 parts by weight to 98 parts by weight of (meth)acrylate having an alkyl group, preferably 93 parts by weight to 100 parts by weight of a total of 100 parts by weight of (meth)acrylate having an alkyl group and (meth)acrylate having an alicyclic group. 98 parts by weight, 93 parts by weight to 97 parts by weight, 2 parts by weight to 10 parts by weight of (meth)acrylate having an alicyclic group, preferably 2 parts by weight to 7 parts by weight, 3 parts by weight to 7 parts by weight. have. In the above range, when the copolymer of the monomer mixture is prepared, the viscosity and molecular weight are at a level suitable for preparing the coating solution, and the peeling force and reliability of the polyolefin-based film at the level required for the product after the coating crude solution is prepared can be secured.

In another embodiment, the monomer mixture consists only of (meth)acrylate having an alkyl group, (meth)acrylate having an alicyclic group, and a comonomer, wherein the comonomer is a (meth)acrylic monomer having a hydroxyl group or a vinyl having a hydroxyl group It may not contain a system monomer.

The comonomer is a monomer different from (meth)acrylate having an alkyl group and (meth)acrylate having an alicyclic group, a monomer having ethylene oxide, a monomer having propylene oxide, a monomer having an amine group, a monomer having an amide group, It may include at least one of a monomer having an alkoxy group, a monomer having a phosphoric acid group, a monomer having a sulfonic acid group, a monomer having a phenyl group, and a monomer having a silane group. The monomer having an ethylene oxide, a monomer having a propylene oxide, a monomer having an amine group, a monomer having an amide group, a monomer having an alkoxy group, a monomer having a phosphoric acid group, a monomer having a sulfonic acid group, a monomer having a phenyl group, a monomer having a silane group are each Conventional types known to those skilled in the art can be employed. The monomer mixture is 89 parts by weight to 93 parts by weight, preferably 92 parts by weight of (meth)acrylate having an alkyl group, out of 100 parts by weight of the total of (meth)acrylate having an alkyl group, (meth)acrylate having an alicyclic group, and a comonomer. 94 parts by weight to 94 parts by weight, 2 parts by weight to 10 parts by weight of (meth)acrylate having an alicyclic group, preferably 3 parts by weight to 7 parts by weight, 1 part by weight to 5 parts by weight of comonomer Preferably 1 part by weight to 3 parts by weight. In the above range, it is possible to secure sufficient peel force in the polyolefin-based film.

The non-hydroxyl group type (meth)acrylic copolymer may be prepared by a conventional method known to those skilled in the art. For example, it can be prepared by adding an initiator to the monomer mixture, and at 25°C to 100°C, solution polymerization, suspension polymerization, photopolymerization, bulk polymerization, dispersion polymerization or emulsion polymerization.

Monofunctional (meth)acrylate may be included in the pressure-sensitive adhesive composition to control the viscosity of the coating solution, thereby implementing the effect of improving the coatability of the pressure-sensitive adhesive composition. When monofunctional (meth)acrylate is included in the monomer mixture for the non-hydroxyl group type (meth)acrylic copolymer, the content in the monomer mixture of (meth)acrylate having an alkyl group is relatively reduced, so that the viscosity of the pressure-sensitive adhesive composition is lowered. The spreadability may not be good. Therefore, the monofunctional (meth)acrylate should be included separately from the non-hydroxyl group type (meth)acrylic copolymer in the pressure-sensitive adhesive composition.

The monofunctional (meth)acrylate may include at least one of (meth)acrylate having an alicyclic group and (meth)acrylate having a heteroalicyclic group. The (meth)acrylate having an alicyclic group is the same as described above in the non-hydroxyl group type (meth)acrylic copolymer. The (meth)acrylate having a heteroalicyclic group may include a (meth)acrylic monomer having a heteroalicyclic group having 3 to 6 carbon atoms and containing at least one hetero element among oxygen, nitrogen, and sulfur. For example, a (meth)acrylic monomer having a morpholine group may be used, and (meth)acryloylmorpholine may be used.

In one embodiment, the monofunctional (meth)acrylate may be a (meth)acrylate having an alicyclic group. The (meth)acrylate having an alicyclic group is 1 part by weight to 50 parts by weight, preferably 10 parts by weight to 30 parts by weight, more preferably 15 parts by weight based on 100 parts by weight of the non-hydroxyl group type (meth)acrylic copolymer. It may be included in an amount of 25 to 25 parts by weight. In the above range, there may be an effect of improving adhesion and peeling force in a polyolefin-based film having non-polar and lipophilic surface properties.

In another embodiment, the monofunctional (meth)acrylate may be a mixture of (meth)acrylate having an alicyclic group and (meth)acrylate having a heteroalicyclic group. (meth)acrylate having a heteroalicyclic group in the mixture: (meth)acrylate having an alicyclic group may be included in a weight ratio of 1:1 to 1:10, preferably 1:2 to 1:6. Within the above range, there may be an effect of improving adhesion to the surface of the polyolefin-based film. In this case, the (meth)acrylate having an alicyclic group may be included in the above-described content range. The (meth)acrylate having a heteroalicyclic group may be included in an amount of 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the non-hydroxyl group-type (meth)acrylic copolymer. In the above range, there may be an effect of improving the adhesion of the pressure-sensitive adhesive film to the base film.

Monofunctional (meth)acrylate is 1 part by weight to 50 parts by weight, preferably 10 parts by weight to 30 parts by weight, more preferably 20 parts by weight to 30 parts by weight based on 100 parts by weight of the non-hydroxyl group type (meth)acrylic copolymer. It may be included in parts by weight. In the above range, there may be an effect of improving the coating property by adjusting the viscosity of the pressure-sensitive adhesive composition.

Among the mixture of the monomer mixture for the non-hydroxyl group type (meth)acrylic copolymer and the monofunctional (meth)acrylate in the pressure-sensitive adhesive composition, the (meth)acrylate having an alicyclic group is 10% to 40% by weight, preferably It may be included in an amount of 14 wt% to 27 wt%. In the above range, the peeling force of the pressure-sensitive adhesive film to the polyolefin-based film may be 100 gf/25 mm or more, and the peeling force is improved for a substrate having non-polar and lipophilic surface properties, and durability is ensured due to excellent adhesion .

The crosslinking agent can achieve the effect of expressing desired physical properties by controlling the cohesive force and peeling force of the adhesive film by crosslinking the non-hydroxyl group-type (meth)acrylic copolymer and the monofunctional (meth)acrylate with each other.

The crosslinking agent is a polyfunctional (meth)acrylate, and may include a bifunctional to hexafunctional (meth)acrylate. For example, the crosslinking agent is 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, Neopentyl glycol adipate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acrylate ) Acrylooxyethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecanedimethanol (meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide modified hexahydrophthalic acid Di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, neopentylglycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate or 9,9-bis[4-( bifunctional (meth)acrylates such as 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 (meth)acrylates such as modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; tetrafunctional (meth)acrylates such as diglycerin tetra(meth)acrylate or pentaerythritoltetra(meth)acrylate; pentafunctional (meth)acrylates such as dipentaerythritol penta(meth)acrylate; Dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate or urethane (meth)acrylate (ex. a reaction product of an isocyanate monomer and trimethylolpropane tri(meth)acrylate) It may contain one or more types of hexafunctional (meth)acrylates such as, etc. Preferably, the crosslinking agent is a non-hydroxyl type, non-hydroxyl group, pentafunctional to hexafunctional crosslinking agent, for example, dipentaerythritol hexa (meth)acrylates can be used.

The crosslinking agent may be included in an amount of more than 0 parts by weight and 1 part by weight or less, preferably 0.001 parts by weight to 1 parts by weight, more preferably 0.001 parts by weight to 0.1 parts by weight based on 100 parts by weight of the non-hydroxyl group type (meth)acrylic copolymer. . In the above range, there may be an effect of improving the adhesion of the adhesive film to the base film and increasing the peeling force.

The silane coupling agent may be included in the pressure-sensitive adhesive composition to improve the peeling force of the pressure-sensitive adhesive film to the polyolefin-based film. As the silane coupling agent, a conventional silane coupling agent known to those skilled in the art may be used. Preferably, the silane coupling agent may be a silane coupling agent having an isocyanate group or a (meth)acryloyl group. The silane coupling agent having an isocyanate group or (meth)acryloyl group increases the peeling force of the adhesive film by crosslinking reaction with at least one of a non-hydroxyl group-type (meth)acrylic copolymer, a monofunctional (meth)acrylate, and a crosslinking agent and increase the effect of improving durability. The silane coupling agent having an isocyanate group may include, but is not limited to, at least one of isocyanatopropyltrimethoxysilane and isocyanatopropyltriethoxysilane. The silane coupling agent having a (meth)acryloyl group may include at least one of (meth)acryloyloxypropyltrimethoxysilane and (meth)acryloyloxypropyltriethoxysilane, but is not limited thereto. does not

The silane coupling agent is included in an amount of more than 0 parts by weight and 1 part by weight or less, preferably 0.001 parts by weight to 1 parts by weight, more preferably 0.1 parts by weight to 0.5 parts by weight based on 100 parts by weight of the non-hydroxyl group type (meth)acrylic copolymer. can In the above range, there may be an effect of increasing the peeling force without reducing the durability.

The pressure-sensitive adhesive composition includes an antistatic agent, a surfactant, a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, a molecular weight regulator, an antioxidant, an anti-aging agent, a stabilizer, a tackifying resin, a modified resin (polyol resin, phenol resin, acrylic resin) , polyester resin, polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, defoaming agent, plasticizer, dye, pigment (color pigment, extender pigment, etc.), processing agent, sunscreen agent, optical brightener, dispersant , a heat stabilizer, a light stabilizer, a UV absorber, a coagulant, a lubricant, and a solvent may further include conventional additives.

The pressure-sensitive adhesive composition may have a viscosity of 300cPs to 50,000cPs at 25°C, and there may be an effect of obtaining excellent coating properties and thickness uniformity in the above range.

The adhesive film may have a glass transition temperature (Tg) of -120°C to -10°C, preferably -100°C to -20°C. In the above range, there may be an effect of good wettability to the adherend surface of the polyolefin-based film and good adhesion. The adhesive film may have a total light transmittance of 90% or more, specifically 95% or more in a visible light region (eg, a wavelength of 380 nm to 780 nm). In the above range, the optical transparency is good, so that it can be used in an optical display device. The adhesive film may have a thickness of 10 μm to 200 μm, preferably 25 μm to 75 μm. In the above range, it may be used by laminating on an optical film.

The pressure-sensitive adhesive film may be prepared by photocuring the pressure-sensitive adhesive composition. For example, the pressure-sensitive adhesive composition is obtained by adding an initiator to the monomer mixture for the non-hydroxyl group-type (meth)acrylic copolymer and polymerization by a predetermined method to obtain the non-hydroxyl group-type (meth)acrylic copolymer, and the monofunctional (meth) ) It can be prepared by mixing the acrylate, the crosslinking agent, and the silane coupling agent and then photocuring.

The optical member according to an embodiment of the present invention includes a polyolefin-based film and an adhesive film laminated on at least one surface of the polyolefin-based film, and the adhesive film may include the adhesive film of the present invention.

The adhesive film may have a peel strength of 100 gf/25 mm or more with respect to the polyolefin-based film. In addition, the pressure-sensitive adhesive film may have excellent peeling force with respect to a polyester-based film including an adherend other than the polyolefin-based film, for example, a polyethylene terephthalate-based film. As described above, the adhesive film has excellent peeling force for different types of adherends, thereby increasing the effectiveness of the adhesive film.

The polyolefin-based film may be an elastomeric polyolefin-based film, for example, a polyolefin-based film containing ethylene vinyl acetate. The polyolefin-based film may be used to encapsulate micro LEDs in which micro-sized LEDs are arranged, but is not limited thereto.

The optical display device of the present invention may include the adhesive film of the present invention. The optical display device may include, but is not limited to, a liquid crystal display device, an organic light emitting device (OLED) display device, a light emitting device display device including a micro light emitting device (LED) display device, and the like.

1 is a cross-sectional view of a micro light emitting device display device according to an embodiment of the present invention. Referring to FIG. 1 , the micro light emitting device display device includes a micro light emitting device panel 10 and a polyolefin-based film 20 and an adhesive film 30 sequentially stacked on the micro light emitting device panel 10, and the adhesive The film 30 may include the adhesive film of the present invention.

The micro light emitting device panel 10 may include a panel in which micro light emitting devices are arranged to form individual pixels. The micro light emitting device panel may be composed of R, G, and B light emitting diodes, and the detailed configuration is as known to those skilled in the art.

The polyolefin-based film 20 and the adhesive film 30 are the same as described above. The adhesive film may be formed directly on the polyolefin-based film. The polyolefin-based film may encapsulate the micro light emitting device in the micro light emitting device panel.

Although not shown in FIG. 1 , a protective film, an adhesive film (eg: PSA, pressure sensitive adhesive), and a functional film having a functional coating layer formed thereon may be additionally formed on the adhesive film 30 . The functional coating layer may be a low-reflection layer, an anti-fingerprint layer, an anti-reflection layer, a hard coating layer, and the like, but is not limited thereto.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any sense.

Example 1

100 parts by weight of a monomer mixture composed of 93 parts by weight of 2-ethylhexyl acrylate, 7 parts by weight of isobornyl acrylate, and 0.005 parts by weight of an initiator Irgacure651 were mixed well in a reactor. After exchanging dissolved oxygen in the reactor with nitrogen gas, the monomer mixture was polymerized by UV irradiation using a low pressure mercury lamp for several seconds, and a non-hydroxyl group-type (meth)acrylic copolymer having a viscosity of 1000 to 3000 cps at 25° C. was prepared. .

To 100 parts by weight (based on solid content) of the non-hydroxyl group type (meth)acrylic copolymer prepared above, 5 parts by weight of acryloylmorpholine, 25 parts by weight of isobornyl acrylate, 0.1 parts by weight of dipentaerythritol hexaacrylate A pressure-sensitive adhesive composition was prepared by mixing 0.1 parts by weight of 3-acryloyloxypropyltrimethoxysilane (KBM-5103) as a silane coupling agent.

A polyethylene terephthalate (PET) film (thickness 75㎛, SKC) is coated with the prepared adhesive composition to a predetermined thickness to form an application layer, and a release film (Toray Advanced Materials, thickness 25㎛) is applied to the application layer. It was laminated, and irradiated with 400 to 1000 mJ/cm ² in a low pressure mercury lamp and 1 to 2 mJ/cm ² in a metal halide lamp to prepare an adhesive sheet in which an adhesive film having a thickness of 25 μm was formed between the PET film and the release film .

Examples 2 to 5 and Comparative Examples 1 to 5

In Example 1, the monomer composition of the non-hydroxyl group-type (meth)acrylic copolymer, the weight average molecular weight of the non-hydroxyl group-type (meth)acrylic copolymer, and the composition of the pressure-sensitive adhesive composition are shown in Table 1 (unit: parts by weight), Table 2 below ( A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that the unit: parts by weight) was changed.

The following physical properties were evaluated for the adhesive films prepared in Examples and Comparative Examples, and the results are shown in Tables 1 and 2 below.

(1) Peel force 1: The release film was peeled from the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples, placed on an ethylene vinyl acetate-based polyolefin-based film (SKC SG00L), and laminated by pressing with a roller of 2 kg. Then, a specimen was prepared by cutting it to a length of 100 mm and a width of 25 mm. The peel strength was evaluated when the adhesive film was peeled from the ethylene vinyl acetate-based polyolefin-based film at a peeling angle of 180°, a peeling angle of 25°C, and a peeling rate of 300 mm/min using a TA (Texture Analyzer) device.

(2) Peel force 2: Peel force 2 in the same manner as in (1), except that in (1), a PET film (Toyobo, A4100) on the untreated side was used instead of the ethylene vinyl acetate-based polyolefin film. was evaluated.

(3) Heat resistance reliability: Peel the release film from the pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples, place it on an ethylene vinyl acetate-based polyolefin-based film (SKC SG00L), and laminate it by pressing 2 kg of roller pressure at 85° C. After standing in the oven for 120 minutes, it was cooled at room temperature for 30 minutes. Then, a specimen was prepared by cutting it to a length of 100 mm and a width of 25 mm. Peel force 3 was measured in the same manner as in (1). Peel force change rate of Equation 1 = |B - A|/A x 100 (in this case, A is peeling force 1, B is peeling force 3) is less than 20%, and bubbles are formed between the ethylene vinyl acetate-based polyolefin-based film and the adhesive film It was judged as good when there was no occurrence, and NG when the peel force change rate was more than 20% or there was bubble generation.

Example 1 Example 2 Example 3 Example 4 Example 5 Monomer mixture of copolymer EHA 93 93 98 97 98 IBOA 7 7 2 3 2 HEA 0 0 0 0 0 Monofunctional (meth)acrylate ACMO 5 5 0 5 5 IBOA 25 25 25 25 15 crosslinking agent DPHA 0.1 0.1 0.1 0.1 0.1 Silane coupling agent 0.1 0.1 0.1 0.1 0.1 Weight average molecular weight of the copolymer 3 million 800,000 800,000 800,000 800,000 Content of IBOA (wt%) 25 25 22 22 14 Peel force 1 (gf/25mm) 100 130 300 300 100 Peel force 2 (gf/25mm) 800 1000 1500 1600 600 Heat Reliability Good Good Good Good Good

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Monomer mixture of copolymer EHA 98 98 93 93 93 IBOA 0 0 7 0 5 HEA 2 2 0 7 2 Monofunctional (meth)acrylate ACMO 5 5 5 5 5 IBOA 25 25 25 25 25 crosslinking agent DPHA 0.1 0.1 0.1 0.1 0.1 Silane coupling agent 0.1 0.1 0 0.1 0.1 Weight average molecular weight of copolymer 3 million 800,000 800,000 800,000 800,000 Content of IBOA (wt%) 19 19 25 19 23 Peel force 1 (gf/25mm) 15 30 80 15 50 Peel force 2 (gf/25mm) 900 1100 1000 850 1000 Heat Reliability NG NG NG NG NG

* In Tables 1 and 2, EHA is 2-ethylhexyl acrylate, IBOA is isobornyl acrylate, and HEA is 2-hydroxyethyl acrylate.

ACMO is acryloylmorpholine, DPHA is dipentaerythritol hexaacrylate.

In Tables 1 and 2, the content of IBOA: the content ratio of IBOA in the mixture of the monomer mixture for the non-hydroxyl group type (meth)acrylic copolymer and the monofunctional (meth)acrylate.

As shown in Table 1, the pressure-sensitive adhesive film of this example had high peeling force with respect to each of the polyolefin-based film and the polyethylene terephthalate film, and had excellent heat resistance reliability.

On the other hand, as shown in Table 2, Comparative Examples 1 to 2 and Comparative Examples 4 to 5 formed of the pressure-sensitive adhesive composition containing the hydroxyl group type (meth)acrylic copolymer instead of the non-hydroxyl group type (meth)acrylic copolymer of the adhesive film had a low peel force with respect to the polyolefin-based film, and the adhesive film of Comparative Example 3 that did not include a silane coupling agent also had a low peel strength with respect to the polyolefin-based film.

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

Claims (16)

An adhesive film formed of a pressure-sensitive adhesive composition comprising a non-hydroxyl group-type (meth)acrylic copolymer, a monofunctional (meth)acrylate, a crosslinking agent and a silane coupling agent,
The adhesive film has a peel force of 100 gf/25 mm or more to the polyolefin-based film,
Among the mixture of the monomer mixture for the non-hydroxyl group type (meth)acrylic copolymer and the monofunctional (meth)acrylate, the (meth)acrylate having an alicyclic group is included in an amount of 10% to 40% by weight, the adhesive film.
The adhesive film according to claim 1, wherein the adhesive film has a peel force of 100 gf/25 mm or more for a polyolefin-based film containing an ethylene vinyl acetate homopolymer or an ethylene vinyl acetate copolymer as the polyolefin-based film.
The adhesive film of claim 1, wherein the adhesive film has a peel force of 500 gf/25 mm or more with respect to the polyester film.
delete The method according to claim 1, wherein the non-hydroxyl group-type (meth)acrylic copolymer comprises a copolymer of a monomer mixture comprising (meth)acrylate having an alkyl group and (meth)acrylate having an alicyclic group, adhesive film.
According to claim 5, wherein the monomer mixture is 90 parts by weight to 98 parts by weight of (meth) acrylate having an alkyl group out of 100 parts by weight of the total of (meth) acrylate having an alkyl group and (meth) acrylate having an alicyclic group The pressure-sensitive adhesive film comprising 2 parts by weight to 10 parts by weight of (meth)acrylate having the alicyclic group.
The pressure-sensitive adhesive film of claim 1, wherein the monofunctional (meth)acrylate includes (meth)acrylate having the alicyclic group.
The adhesive film of claim 7, wherein the monofunctional (meth)acrylate further comprises a (meth)acrylate having a heteroalicyclic group.
The pressure-sensitive adhesive film according to claim 8, wherein the (meth)acrylate having the heteroalicyclic group: the (meth)acrylate having the alicyclic group is included in a weight ratio of 1:1 to 1:10.
The pressure-sensitive adhesive film of claim 1, wherein the crosslinking agent includes a non-hydroxyl group-type 5-functional to 6-functional (meth)acrylate without a hydroxyl group.
The pressure-sensitive adhesive film of claim 1, wherein the silane coupling agent comprises a silane coupling agent having a (meth)acryloyl group or an isocyanate group.
According to claim 1, wherein the pressure-sensitive adhesive composition is 100 parts by weight of the non-hydroxyl group-type (meth)acrylic copolymer, 1 to 50 parts by weight of the monofunctional (meth)acrylate, 0 parts by weight of the crosslinking agent 1 part by weight or less , The pressure-sensitive adhesive film comprising more than 0 parts by weight and 1 part by weight or less of the silane coupling agent.
According to claim 1, wherein the pressure-sensitive adhesive film, the rate of change of the peel force of the following formula 1 will be less than 20%, the pressure-sensitive adhesive film:
<Equation 1>
Rate of change of peel force = ｜B - A｜/A x 100
(In Formula 1, A is the peel force of the adhesive film to the polyolefin-based film (unit: gf/25 mm),
B is the peeling force of the adhesive film to the polyolefin-based film (unit: gf/25mm after leaving the laminate of the adhesive film and the polyolefin-based film at 85° C. for 120 minutes and at 25° C. for 30 minutes) )).
An optical display device comprising the adhesive film of any one of claims 1 to 3 and 5 to 13.
The optical display device of claim 14 , wherein the optical display device is a micro light emitting device optical display device comprising a micro light emitting device panel, a polyolefin-based film sequentially stacked on the micro light emitting device panel, and the adhesive film. .
The optical display device of claim 15 , wherein at least one of a protective film, an adhesive film, and a functional film having a functional coating layer formed on the adhesive film is additionally formed.

Images