KR101693074B1 - Adhesive film, adhesive composition for the same and display comprising the same - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition comprising a cured product of a pressure-sensitive adhesive composition comprising a (meth) acrylic copolymer, having an ASKER C TYPE hardness of 38 to 60 and a gel fraction of 65 to 95% Film, a pressure-sensitive adhesive composition therefor, and a display member comprising the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive film, a pressure-sensitive adhesive composition for the pressure-

The present invention relates to a pressure-sensitive adhesive film, a pressure-sensitive adhesive composition therefor and a display device including the same.

The capacitive touchpad attaches to windows or films placed on top of the screen with a transparent transparent adhesive, which detects the change in capacitance in the window or film and exhibits its characteristics. At this time, problems such as lifting, bubbling, bending, and ITO pattern exposure may occur in the window depending on the type of window, such as glass, PMMA, PC, etc., and various acids present in the transparent transparent adhesive may oxidize ITO The characteristics of the touchpad may be deteriorated due to the increase of the resistance of the ITO. Therefore, the characteristics that minimize the change of the ITO resistance are required

In addition, when bonding the touch panel to the LCD module or the OLED module, minute bubbles may remain, and such bubble removal should be easy. At this time, if the hardness of the adhesive is high, the LCD panel may be pressed and mura may occur.

In this regard, Japanese Laid-Open Patent Application No. 2009-030043 discloses a thermoplastic resin composition comprising an acrylic copolymer (A) containing 20-95 wt% of a structural unit derived from benzyl (meth) acrylate, an epoxy thermosetting resin (B) Discloses an acrylic pressure-sensitive adhesive composition containing a curing agent (C).

An object of the present invention is to provide an adhesive film excellent in printing step difference landing property.

Another object of the present invention is to provide an adhesive film which does not generate bubbles when the touch panel is bonded to a module (LCD or OLED), easily removes the generated bubbles, .

It is still another object of the present invention to provide an adhesive film having little change in resistance and excellent durability in a flat or curved surface.

The pressure-sensitive adhesive film of the present invention is formed of a pressure-sensitive adhesive composition containing a (meth) acrylic copolymer, and has an ASKER C TYPE hardness of 38 to 60 and a gel fraction of 65 to 95% Can be:

<Formula 1>

Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

(In the formula 1, W _A , W _B and W _C are as defined in the following description)

The pressure-sensitive adhesive composition of the present invention comprises 100 parts by weight of a (meth) acrylic copolymer, 0.2 to 0.3 parts by weight of an initiator, and 0.2 to 0.3 parts by weight of a crosslinking agent, and has an ASKER C TYPE hardness of 38 to 60, The gel fraction expressed by the following formula 1 can be 65 to 95%

<Formula 1>

Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

(In the formula 1, W _A , W _B and W _C are as defined in the following description)

The display of the present invention may include the above-mentioned adhesive film.

INDUSTRIAL APPLICABILITY The present invention provides an adhesive film excellent in printing step difference landing property.

The present invention provides an adhesive film excellent in durability without causing air bubbles at the time of joining a touch panel to a module (LCD or OLED), easily removing generated bubbles,

INDUSTRIAL APPLICABILITY The present invention provides a pressure-sensitive adhesive film having a small resistance change and excellent durability when applied to a flat or curved surface.

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

The present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. As used herein, "(meth) acrylate" means both acrylate and methacrylate, "copolymer" means oligomer and polymer,

Hereinafter, the adhesive film of the present invention will be described.

The adhesive film of the present invention may have an ASKER C TYPE hardness of 38 to 60 and a gel fraction of 65 to 95%. When the hardness of the Asuka C type is less than 38 or more than 60, problems such as generation of unevenness due to panel pressing, deterioration in workability in the post-process, occurrence of bubbles at bonding, removal of bubbles generated, and durability in case of curved surface adhesion may occur. When the gel fraction is less than 65% or more than 95%, problems such as occurrence of side defects due to unreacted monomer, initial adhesion deterioration, detachment of peeling force, and durability during curved surface adhesion may occur. For example, the Asuka C type hardness may be 38 to 48 and the gel fraction may be 90 to 95%.

The Asuka C type hardness is obtained by curing the following pressure-sensitive adhesive composition at 5-20 mW / cm ² and 180 W / cm ² at a total light quantity of 3000 mJ / cm ² to obtain an adhesive film having a thickness of 500 탆 or less, for example, 200-500 탆, The laminated film was measured for a film having a total thickness of 5 mm or more, for example, 5-10 mm. The load was 1-10 kgf at the time of measurement, and the value after 30 seconds-1 minute was measured after being installed on a hardness meter. The gel fraction can be expressed by the following formula 1. In measuring the gel fraction, the pressure-sensitive adhesive composition is irradiated with 5-20 mW / cm ² and 180 W / cm ² for 1-10 minutes to measure a total light quantity of 3000 mJ / cm ² , And in measuring the gel fraction, the thickness of the adhesive film may be 500 탆 or less, for example, 200-500 탆:

<Formula 1>

Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

(Where W _A is the weight of the wire mesh,

W _B is the total weight when 0.5 g of the adhesive film obtained after curing the pressure-sensitive adhesive composition is allowed to stand for 1 hour at 35 ° C and a relative humidity of 45%

W _C was prepared by curing the pressure-sensitive adhesive composition, and 0.5 g of the obtained pressure-sensitive adhesive film was allowed to stand for 1 hour at 35 ° C and 45% relative humidity, and placed in a wire net. The sample was placed in a sample bottle containing 50 cc of ethyl acetate, And the weight is measured by drying for 12 hours at 100 占 폚 in a wire mesh state).

The pressure-sensitive adhesive film has a low rate of change in resistance, so that the change in resistance of an electrode film such as ITO can be minimized. In an embodiment, the pressure-sensitive adhesive film may have a rate of change in resistance (R) represented by the following formula (2): 2% or less, for example, 0.5 to 1.8%

<Formula 2>

(Unit: Ω), and P ₂ is a resistance (unit: Ω) measured after leaving the pressure-sensitive adhesive film at 60 ° C. and 90% relative humidity for 240 hours, wherein P ₁ is the initial resistance .

In measuring the rate of change in resistance, the pressure-sensitive adhesive film may be prepared by irradiating the pressure-sensitive adhesive composition at 2000-6000 mJ / cm ² for 1-10 seconds, and the thickness of the pressure-sensitive adhesive film may be 500 탆 or less, have.

The thickness of the adhesive film (thickness excluding the release film) is not limited, but it may be 10 탆 to 2 mm, for example, 100 탆 to 1.5 mm. Within this range, it can be used in a display device. The adhesive film may be transparent. Specifically, the transmittance at a wavelength of 400-700 nm may be 90% or more, for example, 90-99%, and may be used in a display device in the above range.

The adhesive film can be used as optical clear adhesive (OCA) film or touch panel film.

The adhesive film may be made of the pressure sensitive adhesive composition of one embodiment of the present invention. In an embodiment, the pressure sensitive adhesive film is obtained by coating the pressure sensitive adhesive composition of the present invention example on a release film (e.g., polyester, polyethylene terephthalate film) Can be manufactured. In embodiments, UV curing may be performed under conditions of 50 mW / cm ² or less and 6 minutes or less. Preferably, oxygen can be cured in the blocked state. The thickness of the coating is not particularly limited and may be 50 탆 to 2 mm, for example, 50 탆 to 1.5 mm.

Hereinafter, the pressure-sensitive adhesive composition of one embodiment of the present invention will be described. The pressure-sensitive adhesive composition of one embodiment of the present invention may include 100 parts by weight of a (meth) acrylic copolymer having an alkyl group, a hydroxyl group and a heterocyclic group, 0.2 to 0.3 parts by weight of an initiator, and 0.2 to 0.3 parts by weight of a crosslinking agent.

The (meth) acrylic copolymer may be a copolymer of a monomer mixture comprising a (meth) acrylic monomer having an alkyl group, a (meth) acrylic monomer having a hydroxyl group, and a (meth) acrylic monomer having a heteroalicyclic group.

The (meth) acrylic monomer having an alkyl group is an alkyl (meth) acrylate having an unsubstituted C1-C20 alkyl group and may include a (meth) acrylic acid ester having a linear or branched C1-C20 alkyl group. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (Meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl , But are not necessarily limited thereto. These may be included singly or in combination of two or more.

Examples of the (meth) acrylic monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- hydroxypropyl (meth) (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 2-hydroxybutyl (Meth) acrylate having a C 1 -C 20 alkyl group or a C 5 -C 20 cycloalkyl group having a hydroxyl group including a carboxyl group, These may be included singly or in combination of two or more.

The (meth) acrylic monomer having a hetero-alicyclic group is a (meth) acrylate having at least one of nitrogen, oxygen and sulfur and having an alicyclic group having from 2 to 10 carbon atoms. In the specific examples, the (meth) acryloylmorpholine . &Lt; / RTI &gt;

(Meth) acryl-based copolymer is a copolymer comprising 40 to 70% by weight of a (meth) acrylic monomer having an alkyl group, 15 to 50% by weight of a (meth) acrylic monomer having a hydroxyl group, 1 to 15% , And there may be an excellent step-difference landfill and reliable effect in the above-mentioned range. (Meth) acrylic monomer having an alkyl group in an amount of 60 to 70% by weight, a (meth) acrylic monomer having a hydroxyl group in an amount of 25 to 35% by weight and a (meth) acrylic monomer having a heterocyclic group in an amount of 1 to 5% Copolymer of the monomer mixture.

The initiator may be a photopolymerization initiator. The photopolymerization initiator is activated by ultraviolet rays or electron beams to activate a carbon-carbon double bond in the adhesive film to generate a radical reaction. Specific examples include, but are not limited to, alpha-hydroxy ketone type compounds, benzyl ketal type compounds, and mixtures thereof. Hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone, and the like. The initiators may be used alone or in combination of two or more.

The (meth) acrylic copolymer may have a weight average molecular weight of not more than 3,300,000 g / mol, for example, from 2,500 to 3,300,000 g / mol, and may be excellent in excellent step level embedding and reliability in the above range.

The (meth) acrylic copolymer may have a polydispersity index of 2.1 or less, for example, 1.9 to 2.1. In this range, the Asuka hardness can be included in the range of the present invention, and the printed level difference landing property can be good.

The (meth) acrylic copolymer can have a glass transition temperature of -35 to -9 占 폚, for example, -34 to -10 占 폚, excellent workability in the above range, excellent durability and adhesive force.

(Meth) acrylic copolymer can be produced by partial polymerization after the initiator is added to the monomer mixture. The polymerization is carried out until the viscosity of the (meth) acrylic copolymer becomes a viscous liquid having a viscosity of about 1,000-50,000 cPs at 25 ° C. The coating is easy in the viscosity range and the workability is excellent. The polymerization may be carried out by polymerization by UV irradiation, and the initiator may be included in an amount of 0.001-3 parts by weight, preferably 0.003-1 parts by weight, based on 100 parts by weight of the monomer mixture. In this range, low light leakage and excellent endurance reliability can be obtained.

The initiator may be a photopolymerization initiator. The photopolymerization initiator is activated by ultraviolet rays or electron beams to activate a carbon-carbon double bond in the adhesive film to generate a radical reaction. Specific examples include, but are not limited to, alpha-hydroxy ketone type compounds, benzyl ketal type compounds, and mixtures thereof. Hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone, and the like. The initiators may be used alone or in combination of two or more.

The initiator may be contained in an amount of 0.2 to 0.3 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer, and excellent step-difference filling and reliability can be obtained in the above range.

As the crosslinking agent, a polyfunctional (meth) acrylate capable of curing with an active energy ray can be preferably used. Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, (Meth) acrylates such as ethylene oxide modified di (meth) acrylate, di (meth) acryloxy ethyl isocyanurate, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol Di (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylpropane (Meth) acrylate, adamantane (adamantane) di (meth) acrylate or 9,9-bis [4- (2-oxy-yl acrylate) phenyl] fluorene difunctional acrylate and the like; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethylisocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as dipentaerythritol penta (meth) acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (e.g., an isocyanate monomer and trimethylolpropane tri Hexafunctional acrylates such as polyhydric alcohols, polyhydric alcohols, polyhydric alcohols, polyhydric alcohols, polyhydric alcohols, polyhydric alcohols, and the like. (Meth) acrylate.

An isocyanate-based, epoxy-based, aziridine-based, melamine-based, amine-based, imide-based, carbodiimide-based, amide-based cross-linking agent or a combination thereof may be used.

The crosslinking agent may be contained in an amount of 0.2 to 0.3 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer, and excellent step-difference filling and reliability can be obtained within the above range.

The pressure-sensitive adhesive composition may further include a silane coupling agent. The silane coupling agent enhances the adhesion of the adhesive film to a glass plate or the like, and may include, but is not limited to, an epoxy silane coupling agent.

The silane coupling agent may be contained in an amount of 0.05 to 0.2 part by weight, for example, 0.05 to 0.15 part by weight based on 100 parts by weight of the (meth) acrylic copolymer, and excellent step level embedding and reliability can be obtained within the above range.

The pressure-sensitive adhesive composition may optionally contain a silane coupling agent (silane compound), a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, an antioxidant, an antioxidant, a stabilizer, (Coloring pigment, extender pigment, etc.), a treating agent, an ultraviolet ray blocking agent, an antioxidant, an antioxidant, a coloring agent, A fluorescent brightening agent, a dispersing agent, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a lubricant and a solvent.

The pressure-sensitive adhesive composition may have a viscosity at 25 ° C of 1,000 to 50,000 cPs.

The pressure-sensitive adhesive composition can be used for adhesion of an optical film including a polarizing film and a transparent electrode film.

Hereinafter, the pressure-sensitive adhesive composition of another embodiment of the present invention will be described.

In another embodiment of the present invention, the pressure-sensitive adhesive composition may include 100 parts by weight of a (meth) acrylic copolymer having an alkyl group, a hydroxyl group, a hetero-alicyclic group and an alicyclic group, 0.2 to 0.3 parts by weight of an initiator, and 0.2 to 0.3 parts by weight of a crosslinking agent. Is substantially the same as the pressure-sensitive adhesive composition of one embodiment of the present invention, except that the (meth) acrylic copolymer further has an alicyclic group.

(Meth) acrylic copolymer is a copolymer comprising a (meth) acrylic monomer having an alkyl group, a (meth) acrylic monomer having a hydroxyl group, a (meth) acrylic monomer having a heterocyclic group, Copolymer of the mixture. By including a (meth) acrylic copolymer having an alkyl group, a hydroxyl group, a heterocyclic group and an alicyclic group, the pressure-sensitive adhesive composition can realize excellent step-difference embedding and excellent reliability.

The (meth) acrylic monomer having an alicyclic group is a C3-C20 alicyclic (meth) acrylate. Examples thereof include, but are not limited to, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate and the like. These may be included singly or in combination of two or more.

(Meth) acryl-based copolymer is obtained by copolymerizing 43 to 63% by weight of a (meth) acrylic monomer having an alkyl group, 20 to 25% by weight of a (meth) acrylic monomer having a hydroxyl group, 1 to 7% , And 15 to 25% by weight of a (meth) acrylic monomer having an alicyclic group. In this range, it is possible to obtain an excellent stepped embedding and an excellent reliability.

Hereinafter, the display of the present invention will be described. The display of the present invention includes an optical film; And an adhesive film adhered to one side or both sides of the optical film, and the adhesive film may include the adhesive film of the embodiment of the present invention.

Examples of the optical film include a touch panel, a window, a polarizing plate, a color filter, a retardation film, an elliptically polarizing film, a reflective film, an antireflection film, a compensation film, a brightness enhancement film, Transparent electrode films such as plastic LCD substrates, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum doped zinc oxide (AZO), carbon nanotubes (CNT), Ag nanowires and graphene . The method for producing the optical film can be easily manufactured by a person having ordinary skill in the art to which the present invention belongs. For example, a touch panel can be formed by attaching a touch pad to a window or an optical film using the adhesive film. Or may be applied to an ordinary polarizing film as an adhesive film as in the prior art.

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

1, an organic light emitting diode display 100 includes a substrate 10, an OLED element 15 formed on the substrate 10, a sealing layer 20 for sealing the OLED element 15, A first adhesive film 25 formed on the layer 20 and a substrate 35 formed on the first adhesive film 25 and a first transparent conductive layer 40 formed on the substrate 35 and a substrate 35 A polarizing plate 45 formed on the upper portion of the first transparent conductive layer 40 and a second adhesive film 50 formed on the upper portion of the polarizing plate 45. [ And a window 55 formed on top of the second adhesive film 50 and at least one of the first adhesive film 25 and the second adhesive film 50 may be an adhesive film of the embodiment of the present invention .

The substrate 10 may be a substrate (e.g., a TFT substrate) commonly used in an organic light emitting diode display device. Specifically, the substrate 10 may be a glass substrate, a plastic polyimide, an epoxy, an acrylic, It may be a substrate having flexibility.

Although not shown in FIG. 1, the OLED element 15 includes a first electrode, a second electrode, an organic light emitting layer formed between the first electrode and the second electrode, The organic light-emitting film may be formed by sequentially laminating a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer, but is not limited thereto.

The sealing layer 20 protects the OLED element 15 from external moisture or oxygen and may be formed of an inorganic, organic or inorganic / organic mixture.

The transparent conductor includes a base material 35 and a first transparent conductive layer 40 formed on both surfaces of the base material 35 and a second transparent conductive layer 30 can do. The first transparent conductive layer 40 and the second transparent conductive layer 30 may be the same or different from each other. The substrate 35 may be an optical transparent film (e.g., a polyester including polycarbonate, polyethylene terephthalate or the like) And may be an indium tin oxide (ITO) film, or a film containing a metal nanowire. Although not shown in FIG. 1, the first transparent conductive layer 40 and / Or the second transparent conductive layer 30 may be patterned.

The first adhesive film 25 adheres the sealing layer 20 and the second transparent conductive layer 30 and the second adhesive film 50 adheres the first transparent conductive layer 40 and the window 55, May be the same or different, and may include, but not limited to, an adhesive film of one embodiment of the present invention.

The polarizing plate 45 has an anti-reflection function in the organic light emitting display and may include, but not limited to, a polarizer, a protective film formed on the polarizer and / or a retardation film, though not shown in FIG.

The window 55 serves as a display, and may be formed of glass or a plastic material, or may be formed of a material having flexibility.

2 is a cross-sectional view of an OLED display device according to another embodiment of the present invention

2, the OLED display 200 includes a substrate 10, an OLED element 15 formed on the substrate 10, a sealing layer 20 for sealing the OLED element 15, A first adhesive film 25 formed on the layer 20, a substrate 35 formed on the first adhesive film 25, and a first transparent conductive layer 40 formed on the upper side of the substrate 35 A polarizing plate 45 formed on the upper portion of the first transparent conductive layer 40, a second adhesive film 50 formed on the upper portion of the polarizing plate 45, a window 55 formed on the upper portion of the second adhesive film 50, And one or more of the first adhesive film 25 and the second adhesive film 50 may be the adhesive film of the embodiment of the present invention.

Except that the second transparent conductive layer 30 is not included in the organic light emitting diode display device of FIG.

In addition, the OLED display according to embodiments of the present invention can be omitted if there is no seal layer 20 and / or a polarizer 45, and the device can be driven and the display is not damaged.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example  One

, 63 parts by weight of ethylhexyl acrylate (EHA), 15 parts by weight of isobornyl acrylate (IBOA), 20 parts by weight of 2-hydroxyethyl acrylate (HEA), 2 parts by weight of acryloylmorpholine (ACMO) 0.04 part by weight of Irgacure 占 651 (2,2-dimethoxy-2-phenylacetophenone) (manufactured by Shiba Japan K.K.) as an initiator were mixed in a glass container to prepare a monomer mixture. After replacing dissolved oxygen with nitrogen gas, the mixture was partially polymerized by irradiation with ultraviolet light using a low pressure lamp (Sylvania BL Lamp) for several minutes to obtain a viscous liquid having a viscosity of about 15000 cPs.

0.1 parts by weight of epoxy silane (KBM-403: Shinetsu) as a silane coupling agent and 0.26 parts by weight of an additional polymerization initiator IRGACURE 占 651 as a silane coupling agent, HDDA (1,6-hexane diol diacryl 0.02 part by weight) was added to prepare a pressure-sensitive adhesive composition.

The resultant pressure-sensitive adhesive composition was coated on a polyester film (release film) having a thickness of 50 탆 and subjected to mold-releasing treatment to a thickness of 175 탆. After the release film was covered to remove oxygen adversely affecting the intermediate pressure, a transparent pressure-sensitive adhesive film was obtained by irradiating ultraviolet rays to both sides of the release film for about 6 minutes using a low pressure lamp (Sylvania BL Lamp).

Example  2 to 4 and Comparative Example  1 to 5

A pressure-sensitive adhesive film was obtained in the same manner as in Example 1, except that the content of the monomer, the initiator and the crosslinking agent was changed as shown in Table 1 (unit: parts by weight).

Examples and Comparative Examples; The following properties of the adhesive film were evaluated and are shown in Tables 1 and 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Manufacturing method UV curing UV curing UV curing UV curing UV curing UV curing UV curing UV curing UV curing Initiator 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.15 0.15 Cross-linking agent 0.2 0.2 0.2 0.2 0.2 0.05 0.05 0.2 0.2 Silane coupling agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 EHA 63 45 65 43 70 63 45 45 60 IBOA 15 25 0 25 0 15 30 25 15 HEA 20 25 30 25 30 20 20 25 23 ACMO 2 5 5 7 0 2 5 5 2 The weight-average molecular weight of the (meth) acrylic copolymer
(g / mol) 310 million 330 million 3 million 2.9 million 3.5 million 3 million 310 million 330 million 310 million The polydispersity index of the (meth) acrylic copolymer 2.0 2.1 2.1 1.9 2.2 2.5 2.1 2.1 2.0 Glass transition temperature (占 폚) of the (meth) acrylic copolymer -25.8 -10.2 -33.6 -13.4 -40.7 -23.5 -11.5 -10.2 -26.6 Viscosity of the (meth) acrylic copolymer
(cPs, 25 &lt; 0 &gt; C) 1,500 2,000 5,000 2,000 6,000 2,100 1,700 2,000 1,800 Rate of change in resistance
(%) Less than 2 Less than 2 Less than 2 Less than 2 Less than 2 Less than 2 Less than 2 Less than 2 Less than 2 Asuka C type hardness 38 45 42 48 21 30 28 37 31 Whether bubble in lidding O △ O △ O △ X △ △ No △ O O O X △ O △ △ Durability 1 O O O O X X X △ △ Durability 2 △ O △ O X X X X X Gel fraction (%) 92.2 93.3 91.8 93.3 92.2 88.3 87.2 80.3 81.2

Printing step Evaluation items Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Black matrix 2 layer
coating
(10 to 12 μm) Early landfillability O O O O O O O O O Fillability after evaluation of reliability O O O O △ △ △ O O Black Matrix 4 layer
coating
(16 to 20 탆) Early landfillability O O O O O O O O O Fillability after evaluation of reliability O O O O △ X X △ △ Black Matrix 6 layer
coating
(24 to 30 탆) Early landfillability O O O O O △ △ △ △ Fillability after evaluation of reliability O O O △ X X X X X Black Matrix 8 layer
coating
(32 to 40 탆) Early landfillability O O O O O △ △ △ △ Fillability after evaluation of reliability O △ △ △ X X X X X

(1)% change in resistance: The adhesive layer prepared in Examples and Comparative Examples was attached to ITO PET, and electrodes were formed on both sides using silver paste to prepare samples. Thereafter, the initial resistance (P ₁ ) of the manufactured sample was measured, and the resistance (P ₂ ) was measured after allowing the sample to stand at 60 ° C / 90% RH for 240 hours. At this time, the resistance was measured using a Checkman portable resistance, voltage and current measuring device (TaeKwang Electronics Co., Ltd.). Then, the resistance change rate (? R) was measured by substituting the resistance value measured in each of the above conditions into the following equation (2).

<Formula 2>

(Wherein P &_lt; ₁ &gt; and P &_lt; ₂ &gt; are as defined above)

(2) Asuka C type hardness: The adhesive film was measured with a Asker C type hardness meter (ASKER C type, Kobunshi Keiki Co., Ltd.). The adhesive film was prepared by irradiating a total light amount of 3000 mJ / cm ² for ⁵ to ²⁰ mW / cm ² and 180 W / cm ² for 1 to 10 minutes to prepare a 200 μm thick adhesive film. And an adhesive film was laminated so as to have a total thickness of 5 mm. The load at the measurement was 4 kgf, and the value after 30 seconds was measured.

(3) Bubble-bonding at the time of bonding: An adhesive film was laminated on a touch panel, and an LCD module or an OLED module and an adhesive film were laminated. The number of bubbles generated by autoclave was visually observed. When bubbles were not observed, O was observed when microbubbles / stem cells were observed, and X when a large amount of bubbles / stem cells were observed.

(4) Mura: An adhesive film was laminated on a touch panel, and an LCD module and an adhesive film were laminated. When the power was turned on, whether or not a wrinkle pattern or white stain occurred on the LCD panel was visually observed. When no crease pattern or white stain was generated at all, it was evaluated as O, when it occurred a little, &amp;

(5) Durability 1: After bonding the flat PC film / ITO film / glass and PET film, the film was allowed to stand at 60 ° C / 90% relative humidity for 500 hours and then peeled off, Were visually observed and evaluated according to the following criteria.

Good: Good (no bubbles or peeling)

?: Good (bubbles or peeling phenomenon somewhat)

X: poor (large amount of bubbles or peeling occurred)

(6) Durability 2: Surface Plastic Window / Adhesive film / ITO film and PET film were bonded at a temperature of 40 占 폚 or more at 50 占 폚 and left at 85 占 폚 / 85% relative humidity for 500 hours, And the occurrence of bubbling or peeling or bubble formation was visually observed and evaluated according to the following criteria.

○: Good (no bubbles / stalks or lifting effect)

△: Good (slight bubbles / stems or loosening phenomenon somewhat)

X: Poor (a large amount of bubbles / stalks were formed, growth and lifting phenomenon occurred in large quantities)

(7) Gel fraction (%): A pressure-sensitive adhesive composition was applied to a release film at 5-20 mW / cm ² and 180 W / cm ² for 1-10 minutes at a total light quantity of 3000 mJ / cm ² And cured under the manufacturing conditions to prepare an adhesive film having a thickness of 200 mu m. 35 ℃, taking 0.5g of the adhesive film was allowed to stand for 1 hour at a relative humidity condition of 45%, after treatment does not leak 0.5g pre-wrapped with a wire (W _A) measures the weight of the pressure-sensitive adhesive film, measuring the weight (W _B) And placed in a sample bottle. Thereafter, 50 cc of ethyl acetate was added to the sample bottle, and the sample was allowed to stand at 25 占 폚 for one day and dried at 100 占 폚 for 12 hours in a wire mesh state. The weight of the wire net containing the sample was measured (W _C ) Fractions were determined.

<Formula 1> Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

(Wherein W _A , W _B and W _C are as defined above)

(8) Printing step: The black matrix was formed in a screen-coating manner with a rectangular shape having a center portion on the TSP Window Glass. When the black matrix is coated in one layer, the thickness of the black matrix is 5 to 6 μm. In the case of the two-layer coating, the black matrix is coated twice to obtain a black matrix thickness of 10 to 12 μm. The black matrix thickness was measured by Mitutoyo's high accuracy type thickness gage. In Table 2, 4 layer coating, 6 layer coating and 8 layer coating were formed in a similar manner. The adhesive films of the examples and the comparative examples were laminated on the whole of the empty part between the black matrices and between the black matrices to visually confirm the degree of embedding of the level difference according to the height of the black matrix. When lamination was carried out, it was evaluated according to the following criteria whether or not bubbles were lifted or not. The reliability evaluation was carried out by the same method after a lapse of a certain period of time under reliability conditions such as constant temperature and humidity (85 ° C, 85%) and high temperature after lamination.

○: Good (bubbles / stem bubbles, peeling, no whitening)

?: Good (microbubbles / streaking, no whitening)

×: Poor (large amount of bubbles / stem cell formation, growth, lifting, whitening)

As shown in Table 1, the adhesive film of the present invention has an Asuka C type hardness and a gel fraction in a specific range, so that it has excellent printing step difference filling property and durability, less bubble generation at jointing, Can be confirmed. In addition, it was confirmed that there was no defects such as lifting and bubbling when adhering to a film having a three-dimensional curved surface.

On the other hand, the adhesive film of the comparative example deviating from the Asuka hardness and gel fraction of the present invention could not satisfy the effects of the present invention, that is, superior step-difference embedding and reliability.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (14)

(Meth) acryl-based copolymer,
ASKER C TYPE The hardness is 38 to 60,
Sensitive adhesive film having a gel fraction of 65 to 95% represented by the following formula 1:
<Formula 1>
Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100
(Where W _A is the weight of the wire mesh,
W _B is the total weight when 0.5 g of the adhesive film obtained after curing the pressure-sensitive adhesive composition is allowed to stand for 1 hour at 35 ° C and a relative humidity of 45%
W _C was prepared by curing a pressure-sensitive adhesive composition, and 0.5 g of the obtained pressure-sensitive adhesive film was allowed to stand for 1 hour at 35 ° C and 45% relative humidity, and placed in a wire net. The sample was placed in a sample bottle containing 50 cc of ethyl acetate, And is measured by drying in a wire mesh state at 100 DEG C for 12 hours)
Wherein the pressure-sensitive adhesive film has a resistance change rate of 2% or less represented by the following formula (2)
<Formula 2>

(Where P ₁ is an initial resistance (unit: Ω) of the pressure-sensitive adhesive film,
P ₂ is the resistance (unit: Ω) measured after the pressure-sensitive adhesive film is left for 240 hours at 60 ° C. and 90% relative humidity,
The (meth) acrylic copolymer is obtained by copolymerizing 40 to 70 wt% of a (meth) acrylic monomer having an alkyl group, 15 to 50 wt% of a (meth) acrylic monomer having a hydroxyl group, 1 to 15 wt% of a (meth) acrylic monomer having a heterocyclic group % &Lt; / RTI &gt; of the monomer mixture. delete The adhesive film according to claim 1, wherein the adhesive film has a thickness of 10 to 2 mm. The adhesive film according to claim 1, wherein the composition comprises 0.2 to 0.3 parts by weight of an initiator and 0.2 to 0.3 parts by weight of a crosslinking agent based on 100 parts by weight of the (meth) acrylic copolymer. delete The composition of claim 1, wherein the (meth) acrylic copolymer comprises 43 to 63% by weight of a (meth) acrylic monomer having an alkyl group, 20 to 25% by weight of a (meth) acrylic monomer having a hydroxyl group, 1 to 7% by weight of an acrylic monomer, and 15 to 25% by weight of a (meth) acrylic monomer having an alicyclic group. The pressure-sensitive adhesive film according to claim 1, wherein the (meth) acrylic copolymer has a weight-average molecular weight of 3,300,000 g / mol or less and a polydispersity of 2.1 or less. The adhesive film according to claim 1, wherein the (meth) acrylic copolymer has a glass transition temperature of -35 to -9 占 폚. The adhesive film according to claim 1, wherein the composition further comprises an epoxy-based silane coupling agent. (Meth) acrylic copolymer, 0.2 to 0.3 parts by weight of an initiator, and 0.2 to 0.3 parts by weight of a crosslinking agent,
After curing, ASKER C TYPE hardness is 38 to 60,
And a gel fraction represented by the following formula 1 after curing is 65 to 95%
<Formula 1>
Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100
(Where W _A is the weight of the wire mesh,
W _B is the total weight when 0.5 g of the adhesive film obtained after curing the pressure-sensitive adhesive composition is allowed to stand for 1 hour at 35 ° C and a relative humidity of 45%
W _C was prepared by curing a pressure-sensitive adhesive composition, and 0.5 g of the obtained pressure-sensitive adhesive film was allowed to stand for 1 hour at 35 ° C and 45% relative humidity, and placed in a wire net. The sample was placed in a sample bottle containing 50 cc of ethyl acetate, And is measured by drying in a wire mesh state at 100 DEG C for 12 hours)
The (meth) acrylic copolymer is obtained by copolymerizing 40 to 70 wt% of a (meth) acrylic monomer having an alkyl group, 15 to 50 wt% of a (meth) acrylic monomer having a hydroxyl group, 1 to 15 wt% of a (meth) acrylic monomer having a heterocyclic group % Of a monomer mixture,
A pressure-sensitive adhesive composition having a resistance change ratio of 2% or less as shown by the following formula (2) after curing:
<Formula 2>

(Where P ₁ is an initial resistance (unit: Ω) of the pressure-sensitive adhesive film,
P ₂ is the resistance (unit: Ω) measured after the adhesive film was left for 240 hours at 60 ° C. and 90% relative humidity. delete The composition according to claim 10, wherein the (meth) acrylic copolymer comprises 43 to 63% by weight of a (meth) acrylic monomer having an alkyl group, 20 to 25% by weight of a (meth) acrylic monomer having a hydroxyl group, 1 to 7% by weight of an acrylic monomer, and 15 to 25% by weight of a (meth) acrylic monomer having an alicyclic group. The pressure-sensitive adhesive composition according to claim 10, wherein the composition further comprises an epoxy-based silane coupling agent. Optical film; And
The adhesive film according to any one of claims 1, 3, 4, 6, 7, 8, and 9, which is formed on one side or both sides of the optical film, And a pressure-sensitive adhesive film formed from the pressure-sensitive adhesive composition according to any one of claims 12 to 13.

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