KR101385040B1 - Adhesive Composition, Adhesive Film Comprising the Same, Method for Preparing the Adhesive Film and Display Member Using the Same - Google Patents

Abstract

상기식에서, P₂는 60℃/90% 상대습도의 조건에서 240시간 동안 방치한 후 저항이며, P₁은 초기저항임. The pressure-sensitive adhesive composition of the present invention comprises an alicyclic group-containing (meth) acrylic copolymer, a urethane (meth) acrylate, and a crosslinking agent, and after curing, the resistance change (ΔR) represented by the following Equation 1 is less than 5%. . The pressure-sensitive adhesive composition is excellent in durability and cutting properties and can minimize excessive ITO corrosion and at the same time improve the amount of landfill:
[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

Description

Adhesive composition, adhesive film, manufacturing method thereof and display member using the same {Adhesive Composition, Adhesive Film Comprising the Same, Method for Preparing the Adhesive Film and Display Member Using the Same}

The present invention relates to a pressure-sensitive adhesive composition, pressure-sensitive adhesive film, a manufacturing method thereof and an optical member using the same. More specifically, the present invention provides a pressure-sensitive adhesive composition, pressure-sensitive adhesive film, and the like, by introducing a urethane (meth) acrylate into the (meth) acrylic copolymer to improve durability and cutting properties, minimize ITO corrosion, and at the same time, to improve excessive landfill characteristics. It relates to a manufacturing method and an optical member using the same.

The capacitive touch pad is attached to a window or film positioned on an upper surface of the capacitive touch pad and a light-transparent adhesive to detect a change in capacitance in the window or film to exhibit characteristics. Glass, PMMA, PC, etc. may be used as the window, and problems such as lifting, bubble generation, warpage, and ITO patterns may occur when the environment changes depending on the type of the material.

In general, the light-transparent pressure-sensitive adhesive is composed of an acrylic monomer, and includes an acid component such as acrylic acid. Accordingly, various acids present in the light transparent adhesive oxidize ITO on the touch pad side, thereby increasing the resistance of the ITO, thereby lowering the characteristics of the touch pad.

Therefore, there is a demand for development of a pressure-sensitive adhesive suitable for a pressure-sensitive adhesive for touch screens, while having excellent durability and cutting property and effectively suppressing resistance change of the electrode layer under severe conditions.

One object of the present invention is to provide a pressure-sensitive adhesive composition that is excellent in durability and cutting properties and can improve the buried properties while minimizing ITO corrosion.

Another object of the present invention is to provide a pressure-sensitive adhesive composition that can effectively suppress the resistance change of the electrode layer under severe conditions.

Still another object of the present invention is to provide a pressure-sensitive adhesive composition which does not cause end lifting, bubbles, warpage, or light leakage.

Still another object of the present invention is to provide a pressure-sensitive adhesive composition which can be easily coated with a solvent-free type and can thicken a film thickness.

Still another object of the present invention is to provide a display member using the adhesive film.

One aspect of the present invention relates to an adhesive composition. In one embodiment, the pressure-sensitive adhesive composition comprises an alicyclic group-containing (meth) acrylic copolymer, a urethane (meth) acrylate, and a crosslinking agent, and after curing, a resistance change (ΔR) represented by Equation 1 below is less than 5%. Shall be:

[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

The alicyclic group-containing (meth) acrylic copolymer is a C _{1 -20} alkyl (meth) acrylate, cycloaliphatic-containing (meth) acrylate, hydroxyl group-containing monomers and copolymers of one monomer mixture comprising a carboxyl group-containing monomer Can be.

The cycloaliphatic group-containing (meth) acrylic copolymer may include a silane group-containing monomer, maleic acid, caprolactam, acrylonitrile, vinylpyrrolidone, glycidyl methacrylate, acrylamide, acryloyl morpholine, and isocyanoethyl methacrylate. It may further comprise one or more monomer units selected from the group consisting of acrylates.

The pressure-sensitive adhesive composition may include 0.01 to 10 parts by weight of a crosslinking agent based on 100 parts by weight of an acrylic resin including 90 to 99.99% by weight of an alicyclic group-containing (meth) acrylic copolymer and 0.01 to 10% by weight of a urethane (meth) acrylate. .

The urethane (meth) acrylate comprises at least one unit derived from the group consisting of polyether polyols, polyester polyols, and polycaprolactams, and is characterized in that it is at least one functional group.

The urethane (meth) acrylate may be represented by the following formula (1):

[Chemical Formula 1]

(In the above, R1 is hydrogen or methyl group, R2 and R3 are each independently substituted or unsubstituted alkylene having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkylene having 4 to 20 carbon atoms, substituted or unsubstituted carbon atoms 6-20 arylene, X is a group derived from polyester polyol or polyether polyol, n is an integer from 0-20)

The pressure-sensitive adhesive composition may further include a silane-based compound.

The silane-based compound may include at least one or more of an aminosilane coupling agent and an epoxy silane coupling agent.

Another aspect of the present invention relates to an adhesive film formed by curing the pressure-sensitive adhesive composition.

In one embodiment, the adhesive film includes an alicyclic group-containing urethane (meth) acrylic copolymer, and after curing, a resistance change (ΔR) represented by the following Equation 1 is less than 5%:

[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

The adhesive film may have a thickness of 50 μm to 2 mm.

Another aspect of the invention relates to a method for producing the pressure-sensitive adhesive film. The method of C _{1 -20} alkyl (meth) acrylate, cycloaliphatic-containing (meth) acrylate, hydroxyl group-containing monomers, carboxyl group-containing by polymerizing a monomer mixture comprising a monomer alicyclic group-containing (meth) acrylic copolymers To prepare; Preparing a pressure-sensitive adhesive composition by mixing a urethane (meth) acrylate and a crosslinking agent with the alicyclic group-containing (meth) acrylic copolymer; And coating and curing the pressure-sensitive adhesive composition.

In the preparation of the alicyclic group-containing (meth) acrylic copolymer, the monomer mixture may include a silane group-containing monomer, maleic acid, caprolactam, acrylonitrile, vinylpyrrolidone, glycidyl methacrylate, acrylamide, acryloyl morpholine, and It may further comprise at least one monomer selected from the group consisting of isocyanoethyl methacrylate.

When the urethane (meth) acrylate and the crosslinking agent are mixed with the alicyclic group-containing (meth) acrylic copolymer, a silane compound may be added when the pressure-sensitive adhesive composition is prepared.

The curing may be UV curing.

Another aspect of the present invention relates to a display member. Wherein the display member comprises: an optical film; And the adhesive film attached to one or both surfaces of the optical film.

In an embodiment, the optical film may be a polarizing film.

In an embodiment, the optical film may be an ITO film.

The present invention has excellent durability and cutting property, minimizes ITO corrosion and at the same time effectively suppresses the resistance change of the electrode layer under severe conditions, and does not cause end lifting, bubbles, warpage, or light leakage, and is easy to coat with a solvent-free type. Using the pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition capable of thickening the film thickness can provide a pressure-sensitive adhesive film and its manufacturing method. The present invention can also provide a display member using the adhesive film.

Unless stated otherwise in the specification, "(meth) acryl" means that both "acryl" and "methacryl" are possible.

The pressure-sensitive adhesive composition of the present invention is a UV curing type, alicyclic group-containing (meth) acrylic copolymer; Urethane (meth) acrylates; And crosslinking agents. Hereinafter, each component of the present invention will be described in detail below.

Alicyclic group-containing (meth) acrylic copolymer

In embodiments of the monomer mixture including the alicyclic group-containing (meth) acrylic copolymer-containing alkyl (meth) acrylate, cycloaliphatic-containing (meth) acrylate, a hydroxyl group of a C _{1 -20} monomers and carboxyl monomers Copolymer.

Examples of the C _{1 -20} alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (Meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl And is not necessarily limited thereto. These may be used alone or in combination of two or more. Here, (meth) acrylate means both acrylate and methacrylate. Alkyl (meth) acrylate of the above C _{1 -20} may be incorporated at 60 to 95% by weight of the alicyclic group-containing (meth) acrylic copolymer. In the above-mentioned range, bubbles and floating are not generated under heat and humidity conditions, and durability is excellent.

The cycloaliphatic-containing (meth) acrylates include isobornyl (meth) acrylate, carbonyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like, but are not necessarily limited thereto. These may be used alone or in combination of two or more. The cycloaliphatic-containing (meth) acrylate may be included in 0.5 to 20% by weight of the alicyclic group-containing (meth) acrylic copolymer. In the above range, no bubbles or floating occurs under heat and moisture resistant conditions, and have excellent durability.

Examples of the monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). Acrylate, 6-hydroxyhexyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, chloro-2-hydroxypropyl acrylate, diethylene glycol mono (meth) acrylate, allyl Alcohol, and the like, but is not necessarily limited thereto. These may be used alone or in combination of two or more. The monomer having a hydroxy group may be included in 0.5 to 25% by weight of the alicyclic group-containing (meth) acrylic copolymer. Excellent adhesion and durability in the above range, the bubble does not occur even in the humidity conditions.

Examples of the carboxyl group-containing monomers include (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, 4-carboxybutyl (meth) acrylate, itaconic acid, crotonic acid, and maleic acid. And fumaric acid and maleic anhydride. The monomer having a carboxyl group may be included in 0.01 to 10% by weight of the alicyclic group-containing (meth) acrylic copolymer. Preferably it is 0.1 to 3 weight%. It is excellent in the durability and adhesion, resistance resistance to ITO in the above range.

The alicyclic group-containing (meth) acrylic copolymer may be polymerized by addition of other copolymerizable monomers in addition to the above-mentioned monomers. For example, maleic acid, caprolactam, acrylonitrile, vinylpyrrolidone, glycidyl methacrylate, acrylamide, acryloyl morpholine, isocyanoethyl methacrylate, etc. may be used, and phenyl, phenol, cresol A monomer having a high refractive index such as an aromatic (meth) acrylate having a substituent such as may also be added and polymerized as necessary.

In addition, the alicyclic group-containing (meth) acrylic copolymer may be polymerized together by adding a silane group-containing monomer. The said silane group containing monomer has a structure containing a silane group and an unsaturated group. Examples of the silane group-containing monomer may be methacryloxy propyl trimethoxy silane, gamma-meth acryloxy propyl triethoxy silane, vinyl tri (2-methoxy silane), vinyl tri (2-ethoxy silane). ).

Moreover, when a copolymer is manufactured with the monomer which has a hydroxyl group, the monomer containing a silane group and having an isocyanate group can be used. Examples are isocyanate propyltriethoxy silane and the like. The silane group-containing monomer may be included in 0.01 to 10% by weight of the alicyclic group-containing (meth) acrylic copolymer. It is excellent in adhesiveness in the said range, without a physical property fall.

The alicyclic group-containing (meth) acrylic copolymer may have a weight average molecular weight of 100.000 to 3,000,000 g / mol. Excellent adhesion and durability in the above range.

The alicyclic group-containing (meth) acrylic copolymer may have a glass transition temperature (Tg) of -50 to -10 ° C, preferably -30 to -15 ° C. It is excellent in durability adhesiveness in the said range.

Urethane (meth) acrylate

The urethane (meth) acrylate may give a (meth) acrylic copolymer to have a primary crosslinked structure to impart a rigid property and to significantly increase durability. Thus, the urethane (meth) acrylic copolymer partially crosslinked by urethane (meth) acrylate is secondary crosslinked by a crosslinking agent to have an IPN (interpenetrating network) structure. Therefore, it can contribute to more excellent durability to an adhesive.

In an embodiment, the urethane (meth) acrylate includes one or more units derived from the group consisting of polyether polyol, polyester polyol, and polycaprolactam, and is characterized in that it is one or more functional groups. Preferably they are bifunctional-tetrafunctional.

In an embodiment, the urethane (meth) acrylate may be represented by the following Chemical Formula 1:

[Chemical Formula 1]

(In the above, R1 is hydrogen or methyl group, R2 and R3 are each independently substituted or unsubstituted alkylene having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkylene having 4 to 20 carbon atoms, substituted or unsubstituted carbon atoms 6-20 arylene, X is a group derived from polyester polyol or polyether polyol, n is an integer from 0-20)

Examples of the urethane (meth) acrylates include polyester-based urethane (meth) acrylates, polyether-based urethane (meth) acrylates, and polycaprolactam-based urethane (meth) acrylates. These may be used alone or in combination of two or more. The urethane (meth) acrylate constitutes the acrylic resin of the present invention. The acrylic resin may include 90 to 99.99% by weight of an alicyclic group-containing (meth) acrylic copolymer and 0.01 to 10% by weight of a urethane (meth) acrylate. Excellent durability and adhesion in the above range. Preferably the urethane (meth) acrylate is 0.1 to 5% by weight, more preferably 1 to 3% by weight in the acrylic resin.

Cross-linking agent

The pressure-sensitive adhesive composition may be mixed with a crosslinking agent to form a pressure-sensitive adhesive composition.

As the crosslinking agent, a polyfunctional (meth) acrylate capable of curing with an active energy ray may be preferably used.

In a specific example, the polyfunctional (meth) acrylate is 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, Ethylene oxide modified di (meth) acrylate, di (meth) acryloxy ethyl isocyanurate, allylated cyclohexyl di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, dimethylol Dicyclopentanedi (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentylglycol modified trimeth Bifunctional such as propane di (meth) acrylate, adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene Sex acrylates; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethyl isocyanurate; Tetrafunctional acrylates such as 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 (ex. Isocyanate monomers and trimethylolpropane tri (meth) acrylate 6-functional acrylates such as reactants, etc., but are not limited thereto .. These may be used alone or in combination of two or more kinds thereof, in addition to conventional isocyanate, epoxy, aziridine, melamine and amine compounds. , Imide-based, carbodiimide-based, amide-based crosslinking agents or combinations thereof may be used.

In the present invention, the content of the crosslinking agent is 0.01 to 10 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 100 parts by weight of an acrylic resin containing an alicyclic containing (meth) acrylic copolymer and a urethane (meth) acrylate. Preferably it is 0.5-2 weight part.

Initiator

The pressure-sensitive adhesive composition of the present invention may further include an initiator. The initiator may preferably be applied to a photoinitiator. The photoinitiator is activated by ultraviolet rays or electron beams to activate a carbon-carbon double bond in the pressure-sensitive adhesive film to generate a radical reaction. Specific examples include, but are not limited to, alpha-hydroxy ketone type compounds, benzyl ketal type compounds, or mixtures thereof. Preferably, the alpha-hydroxy ketone type compound is 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy 2-methyl-1-phenyl-1-propanone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone and the like can be used. The photoinitiators may be used alone or in combination of two or more thereof. The photoinitiator is 0.001 to 5 parts by weight, more preferably 0.001 to 3 parts by weight, preferably 0.001 to 3 parts by weight based on 100 parts by weight of the acrylic resin including the alicyclic containing (meth) acrylic copolymer and urethane (meth) acrylate. It can be applied in 1 part by weight. Within this range, transparency and excellent durability can be obtained.

Silane compound

As the silane compound, an amino silane coupling agent, an epoxy silane coupling agent or a combination thereof may be used. For example, the silane compound may be 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, (aminoethylaminomethyl) phenethyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3 -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyltriethoxysilane, 3-aminopropylmethyldie Methoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyldimethylethoxysilane, 2,2-dimethoxy-1-aza-2-silacyclopentane-1-ethane Amine, 2,2-diethoxy-1-aza-2-silacyclopentane-1-ethanamine, 2,2-diethoxy-1-aza-2-silacyclopentane, 2,2-dimethoxy-1- Keep it up 2-silacyclopentane, 4-aminophenyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, glycidyl propyltrimethoxy silane, and the like can be used, but are not necessarily limited thereto. These may be used alone or in combination of two or more. The silane-based compound may be used in an amount of 0.01 to 5 parts by weight, preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of an acrylic resin containing an alicyclic containing (meth) acrylic copolymer and a urethane (meth) acrylate. In the above range, durability can be increased, and adhesive strength can be improved. .

The pressure-sensitive adhesive composition may optionally contain a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, an antioxidant, an antioxidant, a stabilizer, and a modified resin (polyol resin, phenol resin, acrylic resin, polyester resin, polyolefin resin). , Epoxy resins, epoxidized polybutadiene resins, etc.), leveling agents, antifoaming agents, plasticizers, dyes, pigments (colored pigments, sieving pigments, etc.), treatment agents, sunscreen agents, optical brighteners, dispersants, thermal stabilizers, light stabilizers, Conventional additives such as ultraviolet absorbers, antistatic agents, lubricants and solvents may be further included.

The urethane (meth) acrylic copolymer of the present invention does not need to be dissolved in a separate solvent during the coating process. That is, since it is applied as a solvent-free process, not only the process is easy and the coating process is easy, but also the manufacture of the adhesive film of 40 micrometers-2 mm thick, for example, 100 micrometers-1.8 mm is possible.

Another aspect of the invention relates to a method for producing the pressure-sensitive adhesive film. The method to prepare the alkyl (meth) acrylate, cycloaliphatic-containing (meth) acrylate, hydroxyl group-containing monomers, carboxyl group-containing monomer polymerizing a monomer mixture containing alicyclic (meth) acrylic copolymers of C _{1 -20} ; Preparing a pressure-sensitive adhesive composition by mixing a urethane (meth) acrylate and a crosslinking agent with the alicyclic group-containing (meth) acrylic copolymer; And coating and curing the pressure-sensitive adhesive composition.

When the urethane (meth) acrylate and the crosslinking agent are mixed with the alicyclic group-containing (meth) acrylic copolymer, a silane compound and an initiator may be added together. The initiator may preferably be applied to a photoinitiator. For example, the above-mentioned alpha-hydroxy ketone type compound, benzyl ketal type compound, or a mixture thereof may be used, but is not limited thereto. Hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone, and the like. These photoinitiators may be used alone or in combination of two or more. The photoinitiator may be applied in an amount of 0.001 to 5 parts by weight, preferably 0.001 to 1 part by weight based on 100 parts by weight of the acrylic resin including the alicyclic containing (meth) acrylic copolymer and urethane (meth) acrylate. Within this range, transparency and excellent durability can be obtained.

The pressure-sensitive adhesive film of the present invention may be formed by curing the pressure-sensitive adhesive composition. For example, after the adhesive composition is coated on a release film, it may be thermally cured or photocured. Preferably UV cured. In an embodiment the UV curing can be carried out under 50mW / cm 2 conditions using a low pressure lamp.

The coating thickness is not particularly limited, and may form an adhesive layer having a thickness of 50 μm to 2 mm, for example, 150 μm to 1.5 mm. In addition, it may be preferably cured in a state in which oxygen is blocked during curing.

The adhesive film thus cured has an IPN crosslinked structure, and the alicyclic group-containing (meth) acrylic copolymer and the urethane acrylate resin are crosslinked to exist in the form of an alicyclic group-containing urethane (meth) acrylic copolymer.

The adhesive film finally cured as described above may have a modulus of 1x10 ⁵ to 5x10 ⁷ dyne / cm ² at 30 ° C. by a frequency sweep test method. In the above range, excellent durability aimed at the present invention can be obtained.

In addition, the adhesive film has a resistance change (ΔR) represented by the following Equation 1 after curing is less than 5%, preferably less than 2%. The term 'curing', when measured using DSC, means that more than 90% of the calorific value of the foreground heat has been generated:

[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

Another aspect of the present invention relates to a display member. Wherein the display member comprises: an optical film; And the adhesive film attached to one or both surfaces of the optical film. The optical film may include a polarizing plate, a color filter, a retardation film, an elliptical polarizing film, a reflection film, an antireflection film, a compensation film, a brightness enhancement film, an alignment film, a light diffusion film, a glass scattering prevention film, a surface protection film, a plastic LCD substrate, ITO film etc. are mentioned. The manufacturing method of the optical film can be easily manufactured by those skilled in the art to which the present invention pertains.

For example, the touch panel may be attached to a window or an optical film by using the adhesive film on a touch pad to form a touch panel. Or it may be applied as an adhesive film to a conventional polarizing film as in the prior art.

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

Example  One

67 parts by weight of ethylhexyl acrylate, 10 parts by weight of isobornyl acrylate, 15 parts by weight of hydroxy ethyl acrylate, 7 parts by weight of maleic acid and Irgacure ™ 651 (2,2-dimethoxy-2- as photopolymerization initiator Phenylacetophenone) (manufactured by Ciba Japan K.K.) was mixed in a glass vessel to prepare a mixture. The mixture was partially polymerized by ultraviolet irradiation using a low pressure lamp (Sylvania BL Lamp) of 50 mw / cm 2 or less to obtain a (meth) acrylic copolymer having a viscosity of about 2,000 cP. 1 part by weight of urethane acrylate (U-2PPA: Shinnakamura Chemical, pencil hardness: 2H) to the resulting (meth) acrylic copolymer, 0.1 part by weight of an epoxy silane compound (KBM-403: manufactured by Shinz Chemical), HDDA as a crosslinking agent The pressure-sensitive adhesive composition was prepared by adding 0.2 part by weight of (1,6-hexanediol diacrylate) and 0.3 part by weight of a polymerization initiator (irgacure 651). The resulting pressure-sensitive adhesive composition was coated onto a 50 μm thick polyester film (release film) to form an adhesive film with a thickness of 175 μm. After covering a 50 μm-thick polyester film (release film) on the adhesive film, the both sides of the release film were irradiated with a low pressure lamp (Sylvania BL Lamp) for 4 minutes to obtain a transparent adhesive film.

Example  2 to 4

Except that the content of the monomer was changed as shown in Table 1 was carried out in the same manner as in Example 1.

Example  5

Dibutyl Tin Dilaurate (DBTDL) catalyst with 62 parts by weight of ethylhexyl acrylate, 10 parts by weight of isobornyl acrylate, 15 parts by weight of hydroxy ethyl acrylate and 7 parts by weight of maleic acid and 5 parts by weight of 3-isocyanatepropyltriethoxysilane 100 ppm was added and reacted at 40 ° C. for 8 hours to prepare a (meth) acrylic copolymer having a silane group. 1 part by weight of urethane acrylate (U-2PPA: Shinnakamura Chemical, pencil hardness: 2H) to the resulting (meth) acrylic copolymer, 0.2 part by weight of HDDA (1,6-hexanediol diacrylate) as a crosslinking agent and polymerization 0.3 parts by weight of an initiator (irgacure 651) was added to prepare an adhesive composition, and then a film was prepared in the same manner as in Example 1.

Example  6

It carried out similarly to Example 1 except having changed the urethane acrylate (U-412A: Shin-Nakamura Chemical, pencil hardness: 6B).

Comparative Example  1-3

Except that the content of the monomer was changed as shown in Table 1 was carried out in the same manner as in Example 1.

Example Comparative Example One 2 3 4 5 6 One 2 3 Acrylic resin EHA 67 64 66 60 62 67 68 63 67 IBOA 10 12 10 10 10 10 10 10 - HEA 15 15 15 15 15 15 15 15 15 AA - One - - - - - 5 One MA 7 7 7 7 7 7 7 7 7 Contains silane group
Monomer - - - - 5 Urethane acrylate U-2PPA One One 2 8 One - - - 10 U-412A - - - - - One - - - Silane compound 0.1 - 0.1 0.1 - 0.1 0.1 0.1 0.1 Initiator 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Cross-linking agent 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Resistance change (△%)  <3 <3  <3 <3  <3  <3 <3 8 <3 Peel strength 2030 1810 1900 1400 2300 2200 2100 2600 1300 durability O O O O O O X O X Modulus
(x10 ⁵ ) 5.2 5.6 5.3 6.2 6.0 5.0 4.6 5.7 5.4

EHA: ethylhexyl acrylate

IBOA: Isobonylacrylate

HEA: hydroxy ethyl acrylate

AA: Acrylic acid

MA: Maleic acid

Silane group-containing monomer: 3-isocyanate propyl triethoxy silane

Property evaluation

(1) Resistance change: The prepared adhesive film was attached to ITO PET, and a sample was prepared by forming electrodes using silver paste on both sides. Thereafter, the initial resistance (P1) was measured on the cured sample, and the sample was left for 240 hours under the condition of 60 ° C / 90% RH, and then the resistance (P2) was measured. At this time, the resistance was measured using a Checkman portable resistance, voltage, and current measuring instrument (made by Taekwang Electronics). Then, the resistance change rate (ΔR) was measured by substituting the resistance value measured under each condition as shown in Equation 1 below:

[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

(2) Using a PET film (backing film) having a thickness of 50 μm in peeling strength (gf / 25 mm), the prepared adhesive film was attached to the ITO film, and at 30 minutes after the attachment, TA.XT_Plus Texture Analyzer Peeling force was measured using (Stable Micro System (made)). Peel force was measured at a rate of 300 mm / min.

(3) Durability: After bonding PC film / ITO film / Glass and PET film, it is allowed to stand at 60 ^o C / 90% relative humidity for 500 hours, and then there is no lifting or peeling or bubbles on the surface. Observed visually and evaluated by the following criteria.

Good: Good (no bubbles or peeling)

?: Good (bubbles or peeling phenomenon somewhat)

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

(4) Modulus (dyne / cm ² ): Each sample was made of a specimen of diameter 8mm and subjected to a frequency sweep test to measure the storage modulus at 1 rad / s at 30 ℃.

As shown in Table 1, the example has a low resistance change and excellent peel strength, durability, and modulus, whereas Comparative Example 1 without applying urethane (meth) acrylate was inferior in durability, and urethane (meth) acrylate. Instead, Comparative Example 2, in which the amount of acrylic acid was increased, increased durability, but the resistance change was remarkably increased. In addition, it can be seen that in Comparative Example 3 in which urethane acrylate was applied and no alicyclic containing (meth) acrylate was applied, peeling strength and durability were significantly reduced.

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 (18)

Pressure-sensitive adhesive composition containing an alicyclic group-containing (meth) acrylic copolymer, a urethane (meth) acrylate and a crosslinking agent, and having a resistance change (ΔR) of less than 5% represented by the following formula 1 after curing:
[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.

The cycloaliphatic group-containing (meth) acrylic copolymer according to claim 1, wherein the alicyclic group-containing (meth) acrylic copolymer comprises a C _1-20 alkyl (meth) acrylate, an alicyclic containing (meth) acrylate, a hydroxyl group-containing monomer and a carboxyl group-containing monomer. Pressure-sensitive adhesive composition, characterized in that the copolymer of the monomer mixture.
According to claim 1, wherein the cycloaliphatic group-containing (meth) acrylic copolymer is a silane group-containing monomer, maleic acid, caprolactam, acrylonitrile, vinylpyrrolidone, glycidyl methacrylate, acrylamide, acryloyl morpholine And at least one monomer unit selected from the group consisting of isocyanoethyl methacrylate.
According to claim 1, wherein the pressure-sensitive adhesive composition is 0.01 to 10 crosslinking agent with respect to 100 parts by weight of acrylic resin containing 90 to 99.99% by weight of the alicyclic group-containing (meth) acrylic copolymer and 0.01 to 10% by weight of urethane (meth) acrylate Pressure-sensitive adhesive composition comprising a weight part.
The pressure-sensitive adhesive composition of claim 1, wherein the urethane (meth) acrylate comprises at least one unit derived from the group consisting of polyether polyols, polyester polyols, and polycaprolactams, and has at least one functional unit.
The pressure-sensitive adhesive composition of claim 1, wherein the urethane (meth) acrylate is represented by the following Chemical Formula 1:
[Chemical Formula 1]

(In the above, R1 is hydrogen or methyl group, R2 and R3 are each independently substituted or unsubstituted alkylene having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkylene having 4 to 20 carbon atoms, substituted or unsubstituted carbon atoms 6-20 arylene, X is a group derived from polyester polyol or polyether polyol, n is an integer of 0-20).
The pressure-sensitive adhesive composition of claim 1, wherein the pressure-sensitive adhesive composition further comprises a silane compound.
The pressure-sensitive adhesive composition of claim 7, wherein the silane compound comprises at least one of an aminosilane coupling agent and an epoxy silane coupling agent.
The adhesive film formed by hardening | curing the adhesive composition of any one of Claims 1-8.
An adhesive film containing an alicyclic group-containing urethane (meth) acrylic copolymer and having a resistance change (ΔR) of less than 5% represented by the following Equation 1 after curing:
[Equation 1]

In the above formula, P ₂ is the resistance after standing for 240 hours at 60 ℃ / 90% relative humidity conditions, P ₁ is the initial resistance.
The pressure-sensitive adhesive film of claim 10, wherein the pressure-sensitive adhesive film has a thickness of 50 μm to 2 mm.
Alkyl (meth) acrylates of C _{1 -20,} cycloaliphatic-containing (meth) acrylate, hydroxyl group-containing monomer, by polymerizing a monomer mixture comprising a carboxyl group-containing monomer to prepare the alicyclic group-containing (meth) acrylic copolymers ;
Preparing a pressure-sensitive adhesive composition by mixing a urethane (meth) acrylate and a crosslinking agent with the alicyclic group-containing (meth) acrylic copolymer; And
Coating and curing the pressure-sensitive adhesive composition;
Method of producing an adhesive film comprising the step.
The method of claim 12, wherein the monomer mixture in the preparation of the alicyclic group-containing (meth) acrylic copolymer is a silane group-containing monomer, maleic acid, caprolactam, acrylonitrile, vinylpyrrolidone, glycidyl methacrylate, acrylamide , Acryloyl morpholine and isocyanoethyl methacrylate further comprising at least one monomer selected from the group consisting of.
The method according to claim 12, wherein in the preparation of the pressure-sensitive adhesive composition by adding a urethane (meth) acrylate and a crosslinking agent to the alicyclic group-containing (meth) acrylic copolymer, a silane compound is added.
13. The method of claim 12, wherein said curing is UV curing.
Optical film; And
The adhesive film of claim 9 attached to one or both surfaces of the optical film;
Display member comprising a.
The display member of claim 16, wherein the optical film is a polarizing film.

The display member according to claim 16, wherein the optical film is an ITO film.