KR101411014B1 - Optically adhesive composition, optically adhesive film prepared from the same, and display panel comprising the same - Google Patents

Abstract

The present invention relates to an optical pressure-sensitive adhesive film comprising a urethane (meth) acrylate copolymer having a hydroxyl group and a vinyl group at the end thereof to solve the distortion problem by increasing elongation and tensile strength.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical adhesive composition, an optical adhesive film formed therefrom, and a display panel comprising the optical adhesive composition,

The present invention relates to an optical adhesive composition, an optical adhesive film produced therefrom, and a display panel comprising the same. More specifically, the present invention relates to an optical pressure-sensitive adhesive composition which solves warpage problems by increasing elongation and tensile strength, an optical pressure-sensitive adhesive film made therefrom, and a display panel comprising the same.

2. Description of the Related Art [0002] With the recent development of electric and electronic and communication technologies, various electronic devices utilizing a touch window device in which a touch panel and an LCD window panel are integrally combined are widely developed and popularized. In the past, an optical clear adhesive film (OCA) was used between a window glass and a touch screen panel sensor glass. OCA film is used for interlayer adhesion or touch screen attachment of mobile phone to build up parts when making LCD. OCA film transmits more than 97% of light and functions like glass, but also improves the sharpness of the screen compared with the conventional double-sided tape and has good adhesion.

However, with the development of various shapes of mobile phones, there are restrictions on the use of OCA films, and the need to lower the prices of expensive OCA films is emerging. In addition, since the conventional OCA film has the inherent limit of a solid type transparent tape, even if the producer side tries to make a fine effort to adhere to the interlayer surface between the window panel and the touch panel, air bubbles may be generated by the instantaneous air inflow .

In order to solve this problem, there has been proposed a method of replacing the OCA film with a resin-type liquid optical curing type adhesive, which is not a film type.

It is an object of the present invention to provide an optical adhesive composition capable of solving the problem of warping after curing.

Another object of the present invention is to provide an optical adhesive film made of the above optical adhesive composition.

It is still another object of the present invention to provide a display panel comprising the optical pressure-sensitive adhesive composition.

The optical pressure-sensitive adhesive composition of the present invention comprises a urethane (meth) acrylate copolymer, a reactive monomer, and an initiator, and may have an elongation of 200-800% and a tensile strength of 10 gf / mm ² or less when formed into a film after curing.

In one embodiment, the urethane (meth) acrylate copolymer may be a copolymer of a polyol, an isocyanate compound represented by the following formula (1), and a monomer having an isocyanate group and a vinyl group.

≪ Formula 1 >

Wherein R1, R2 and R3 are independently of each other - (CH2) n- and n is an integer from 1-10.

In one embodiment, the urethane (meth) acrylate copolymer may be further polymerized with a monomer having a silane group and an isocyanate group.

In one embodiment, the pressure sensitive adhesive composition may further comprise a silane coupling agent.

The pressure sensitive adhesive film of the present invention can be produced from the above optical pressure sensitive adhesive composition.

The display panel of the present invention may comprise the optical pressure-sensitive adhesive composition.

The present invention solves the distortion problem in the optical adhesive film. The present invention provides an optical pressure-sensitive adhesive film which can be used as an optical pressure-sensitive adhesive film for medium and large-sized displays.

1-3 are plan views of the optical pressure-sensitive adhesive composition of Example 1, Comparative Example 1 and Comparative Example 2, respectively, after photo-curing.

The optical pressure-sensitive adhesive composition according to one aspect of the present invention comprises a urethane (meth) acrylate copolymer, a reactive monomer, and an initiator. When the film is formed into a film after curing, the elongation may be 200-800% and the tensile strength may be 10 gf / have.

The optical pressure-sensitive adhesive film, which is another aspect of the present invention, may include a film formed by curing a pressure-sensitive adhesive composition while adhering the adherend when the pressure-sensitive adhesive composition is cured, for example, between a glass and a transparent conductive film.

The method of measuring the elongation and tensile strength is not particularly limited.

Elongation and tensile strength can be measured by the ASTM D638 method. For example, a pressure-sensitive adhesive composition is coated on a PET (polyethylene terephthalate) release film. After curing at 3000-5000 mJ / cm < 2 >, measurement is made from an optical pressure-sensitive adhesive film having a thickness of 500 mu m.

When the elongation is less than 200%, the pressure-sensitive adhesive layer tends to shrink after the two adherends are attached. If the elongation is more than 800%, the coating is too soft and tacky to exhibit poor properties during rework.

When the tensile strength exceeds 10 gf / mm 2, the strength of the coating film is strong, so that the impact resistance of the display product is insufficient and the adhesion force is also lowered.

Preferably, the elongation can be 400-710% and the tensile strength can be 0.1-10 gf / mm < 2 >.

The optical pressure-sensitive adhesive composition of the present invention may be applied or injected into a part of the adherend to be adhered in a liquid form having a viscosity of 500 to 20,000 cps at 25 캜. In addition, the pressure-sensitive adhesive composition may be coated on a PET (polyethylene terephthalate) release film to be used in a film form.

The optical pressure-sensitive adhesive film of the present invention may be formed of a pressure-sensitive adhesive composition comprising a urethane (meth) acrylate copolymer, a reactive monomer and an initiator.

urethane ( Meta ) Acrylate  Copolymer

The urethane (meth) acrylate copolymer contains a hydroxyl group and a vinyl group. In particular, a hydroxy group and a vinyl group are contained at the end of the copolymer.

Urethane (meth) acrylate copolymers include urethane polyols; And a (meth) acrylic monomer having an isocyanate group and a vinyl group terminal. The urethane polyol may be a copolymer obtained by copolymerizing a polyol and an isocyanate-based compound.

For example, a urethane (meth) acrylate copolymer prepolymerizes a polyol and an isocyanate compound of Formula 1 to prepare a urethane polyol. And then polymerizing a (meth) acrylic monomer having an isocyanate group and a vinyl group.

The urethane polyol has a urethane bond and a hydroxyl group. The urethane polyol is produced by polymerizing an excess amount of a polyol and a relatively small amount of an isocyanate compound, and thus has a hydroxyl group end together with a urethane bond.

The urethane (meth) acrylate copolymer has a hydroxyl group and a vinyl group because the hydroxyl group of the urethane polyol polymerizes with the (meth) acrylic monomer having the isocyanate group and the vinyl group to form a urethane bond.

The weight average molecular weight of the urethane (meth) acrylate copolymer may be from 5,000 to 50,000 g / mol.

The urethane (meth) acrylate copolymer may be contained in an amount of 35 to 93.45% by weight based on the solid content of the optical adhesive composition. Within this range, the main properties of the urethane binder are high elongation, low tensile strength and low cure shrinkage. Preferably 77-87% by weight.

In the preparation of the urethane (meth) acrylate copolymer, the equivalent ratio of the polyol, isocyanate compound, and isocyanate group and (meth) acrylic monomer having a vinyl group can be appropriately controlled. For example, the (meth) acrylic monomer having a polyol: isocyanate compound: isocyanate group and a vinyl group may be polymerized in an equivalent ratio of 1: 0.75 to 0.85: 0.15 to 0.25. Within this range, the main properties of the urethane binder are high elongation, low tensile strength and low cure shrinkage.

The polyol may be at least one selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polytetramethylene glycol, tetramethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6- hexanediol, neopentyl glycol, polycarbonate polyol , Polyester polyol, and 1,4-cyclohexanedimethanol, but is not limited thereto.

The isocyanate compound is preferably a compound having two or more isocyanate groups.

Specifically, the isocyanate compound may be an isocyanate compound (A) represented by the following formula (1).

≪ Formula 1 >

Wherein R1, R2 and R3 are independently of each other - (CH2) n- and n is an integer from 1-10.

The isocyanate compound of formula (1) can be purchased as a commercially available product (AE700-100, ASAHI KASEI).

The isocyanate compound may be a mixture of the isocyanate compound (A) of the above formula (1) and the compound (B) having two or more isocyanate groups.

The compound (B) having two or more isocyanate groups includes at least one compound selected from the group consisting of biuret type, isocyanurate type and adduct type as described below. can do.

* Burette type:

* Isocyanurate type:

* A duct type:

(Wherein R 1, R 2 and R 3 are each independently - (CH 2) n -, n is an integer of 1-20, and R 4 is hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, )

The compound (B) having two or more isocyanate groups may include at least one compound selected from the group consisting of common diisocyanate compounds such as isoprene, hexamethylene, and toluene compounds. Specifically, the diisocyanate compound is preferably selected from the group consisting of toluene diisocyanate including 2,4 or 2,6 toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, Methane diisocyanate, naphthalene diisocyanate, and 2,4-toluene diisocyanate.

The (meth) acrylic monomer having an isocyanate group and a vinyl group may be at least one member selected from the group consisting of 2- (meth) acryloyloxyethyl isocyanate (MOI) and 3-isocyanatopropyl (meth) acrylate , But are not limited thereto.

The polymerization reaction of the polyol, the isocyanate compound and the (meth) acrylic monomer having an isocyanate group and a vinyl group can be carried out by conventional polymerization methods such as bulk polymerization, emulsion polymerization, suspension polymerization and the like, and there is no particular limitation. The polymerization reaction can be carried out, for example, at 40-80 DEG C for 2-24 hours.

The polymerization reaction can be carried out in the absence of a catalyst or in the presence of a catalyst, preferably a catalyst is used to prepare the copolymer. The catalyst may be at least one selected from the group consisting of dibutyltin dilaurate (DBTDL), triethylenediamine (TEDA), 1,4-azabicyclo [2.2.2] octane, But are not limited thereto. The catalyst may be used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the isocyanate compound.

The urethane (meth) acrylate copolymer may further include a monomer having a silane group and an isocyanate group. The monomer having a silane group bonds with the hydroxyl group of the urethane (meth) acrylate copolymer. The silane group and the monomer having an isocyanate group may be, for example, 3-isocyanatopropyltriethoxysilane, but are not limited thereto. The monomer having a silane group may be polymerized in an amount of 0.1 to 2 equivalents based on 1 equivalent of the polyol.

Reactive monomer

The reactive monomer may be a reactive (meth) acrylate monomer.

The reactive monomer may include at least one member selected from the group consisting of a vinyl monomer having a hydroxy group, a vinyl monomer having an alkyl group, a vinyl monomer having a carboxyl group, and a vinyl monomer having a vinyl group and a silane group.

Preferably, the reactive monomer may include a vinyl-based monomer having a hydroxyl group, a vinyl-based monomer having an alicyclic group among the vinyl-based monomers having an alkyl group, a vinyl-based monomer having a carboxyl group, and a vinyl-based monomer having a vinyl group and a silane group .

The reactive monomer may be contained in an amount of 5 to 45% by weight based on the solid content of the optical adhesive composition. The viscosity of the material is controlled within the above range to improve the workability and the value of the shrinkage ratio can be shown within the above range. Preferably 8 to 38% by weight.

The vinyl monomer having a hydroxyl group may be a (meth) acrylic acid ester having a terminal or an alkyl group having 2 to 20 carbon atoms and having a hydroxy group in the structure. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 6- 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, (Meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylol propane di (meth) acrylate, diethylene glycol mono (Meth) acrylate, trimethylol ethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, and cyclohexane dimethanol mono Above But hamhal, but is not limited to these.

The vinyl monomer having a hydroxyl group may be contained in an amount of 1 to 25% by weight, preferably 2 to 19% by weight, of the optical adhesive composition. Within the above range, a desired modulus can be obtained after curing.

The vinyl monomer having an alkyl group may be a (meth) acrylic acid ester having a cyclic alkyl group having 1 to 20 carbon atoms in linear or branched form, a (meth) acrylic acid ester having a monocyclic or heterocyclic alicyclic ring having 4 to 20 carbon atoms , (Meth) acrylic monomers having an alicyclic ring having 4 to 20 carbon atoms and containing at least one hetero atom selected from the group consisting of nitrogen, oxygen and sulfur, or a mixture thereof.

Preferably, the vinyl monomer having an alkyl group is a (meth) acrylic acid ester having an alicyclic ring having 6 to 20 carbon atoms and a (meth) acrylic acid ester having a heteroalicyclic ring having 4 to 6 carbon atoms and containing nitrogen, And may include an acrylic monomer.

For example, the vinyl monomer having an alkyl group may be an isobornyl (meth) acrylate, an acryloylmorpholine, a cyclohexyl (meth) acrylate, a cyclopentyl (meth) acrylate, (Meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and lauryl , But are not limited thereto. ≪ tb > < TABLE >

The vinyl monomer having an alkyl group may be contained in an amount of 1 to 20% by weight, preferably 3 to 14% by weight, in the optical adhesive composition. Within the above range, workability during coating is easy and a low shrinkage ratio can be obtained when cured.

The vinyl monomer having a carboxyl group includes, for example, a group consisting of? -Carboxyethyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl acetic acid, (meth) acrylic acid, fumaric acid, , But is not limited thereto.

The vinyl monomer having a carboxyl group may be contained in an amount of 1 to 10% by weight, preferably 3 to 5% by weight, in the optical adhesive composition. Within the above range, workability in coating is easy and a low shrinkage ratio can be obtained in curing.

The vinyl monomer having a vinyl group and a silane group can increase the adhesion to glass. These monomers include, but are not limited to, "(R1) (R2) (R3) Si- (CH2) m- (OOC) p- An alkyl group or an alkoxy group having 1 to 10 carbon atoms, m is 0 to 10, and p is 0 to 10.).

For example, the vinyl-based monomer having a vinyl group and a silane group may include at least one member selected from the group consisting of vinyl trichlorosilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, and vinyltriethoxysilane However, it is not limited thereto.

The monomer having a vinyl group and a silane group may be contained in an amount of 1-20% by weight in the optical adhesive composition. Within the above range, workability in coating is easy and a low shrinkage ratio can be obtained in curing.

Initiator

The initiator can be used without limitation as long as it can exhibit an excellent photoreaction at an ultraviolet wavelength band of 150 nm to 500 nm. The initiator may comprise a photoinitiator.

The initiator may be, for example, at least one selected from the group consisting of acetophenone, benzophenone, triazine, thioxanthone, benzoin, and oxime compounds, but is not limited thereto. For example, 1-hydroxycyclohexyl phenyl ketone, oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] -ethyl ester, benzophenone, 4-phenylbenzophenone, hydroxybenzophenone, Benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, 4,4'-bis (dimethylamino) benzophenone, 2,2'-diethoxy Acetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 2,4,6-trichloro-s-triazine, (Trichloromethyl) -s-triazine, thioxanthone, 2-methylthioxanthone, 2-methylthioxanthone, , Benzoin or benzoin methyl ether may be used.

The initiator may be contained in an amount of 1-20% by weight, preferably 5-8% by weight, based on the solid content of the optical pressure-sensitive adhesive composition. Within this range, the film after curing upon exposure to UV exhibits high elongation, low tensile strength and low shrinkage

The optical adhesive composition of the present invention may further comprise at least one member selected from the group consisting of an ultraviolet absorber and an antioxidant.

Ultraviolet absorber

The ultraviolet absorber has a role of improving the photostability of the pressure-sensitive adhesive composition. The ultraviolet absorber may include at least one selected from the group consisting of benzotriazole, benzophenone and triazine, but is not limited thereto. For example, the ultraviolet absorber may be selected from the group consisting of 7 to 9 linear or branched alkyl (meth) acrylates of 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) 4- Esters, 2- (benzotriazol-2-yl) -4- (2,4,4-trimethylpentan-2-yl) phenol, 2- (2'- 2- [2'-hydroxy-3 ', 5'-di-t-butyl (2'-hydroxybenzotriazole) Phenyl) benzotriazole, 2,4-hydroxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- 1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) 2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, and the like.

The ultraviolet absorber may be contained in an amount of 0.1 to 5% by weight, preferably 0.1 to 1% by weight, based on the solid content of the optical pressure-sensitive adhesive composition. Within the above range, the yellowing of the surface of the film after curing can be prevented.

Antioxidant

The antioxidant serves to prevent the oxidation of the pressure-sensitive adhesive composition and to improve the thermal stability. The antioxidant may include, but is not limited to, at least one selected from the group consisting of a phenol compound, a quinone compound, an amine compound, and a phosphite compound. Examples of the antioxidant include pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), tris (2,4- ) Phosphite, and the like.

The antioxidant may be contained in an amount of 0.01 to 5% by weight, preferably 0.01 to 1% by weight, based on the solid content of the optical adhesive composition. Within the above range, the film after curing is prevented from being aged and exhibits excellent thermal stability.

The optical adhesive composition may further include a silane coupling agent for enhancing adhesion with a window glass.

As the silane coupling agent, those known as conventional silane coupling agents can be used. For example, a silane coupling agent containing a vinyl group or a mercapto group can be used. Examples thereof include polymerizable fluorinated group-containing silicon compounds such as trimethoxysilane, vinyltriethoxysilane and (meth) acryloxypropyltrimethoxysilane; Silicon compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; Containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane. ; And 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto.

The silane coupling agent may be contained in an amount of 0.1 to 6 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the optical adhesive composition. And exhibits excellent adhesion when adhered to glass within the above range.

The optical pressure-sensitive adhesive composition may have a hardening shrinkage of 1% or less. When the area is widened within the above range, the problem of warpage occurring after curing of the optical adhesive film can be solved.

The curing shrinkage ratio measures the specific gravity of the liquid composition before curing the optical pressure-sensitive adhesive composition. The optical pressure-sensitive adhesive composition is coated on a release film containing PET (polyethylene terephthalate) and cured at 3000 to 5000 mJ / cm 2 to prepare an optical pressure-sensitive adhesive film having a thickness of 200 μm. The release film is removed, and the specific gravity is measured for an optical adhesive film having a thickness of 200 mu m. The hardening shrinkage ratio is obtained by the following formula (1).

<Formula 1>

Cure shrinkage ratio = [(specific gravity of liquid composition before curing-specific gravity of solid after curing)] / specific gravity of liquid composition before curing x 100

Preferably, the curing shrinkage ratio may be 0.1-0.7%.

The optical pressure sensitive adhesive composition can solve the warpage problem that has become a problem after the photo-curing in the conventional large-sized non-mobile type displays by increasing the elongation, lowering the tensile strength and lowering the shrinkage ratio.

The optical pressure-sensitive adhesive composition may have a viscosity of 500 to 20,000 cps at 25 占 폚. Preferably 500-5,000 cps.

Another aspect of the present invention relates to a display panel. The display panel may include the optical pressure-sensitive adhesive film. The display panel may be manufactured by, but not limited to, filling the optical pressure-sensitive adhesive composition between the window glass layer and the ITO film and curing at 2000-6000 mJ / cm &lt; 2 &gt;.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Manufacturing example  1: urethane ( Meta ) Acrylate  Copolymer production

80 g of polypropylene diol and 10 g of 1,4-butanediol were initially charged in a 2 L four-necked flask, and a reflux condenser, a thermometer, and a dropping funnel were provided on one side and the other side. After the temperature of the flask solution was raised to 60 캜, 1.3 g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration was added to toluene. Subsequently, 6 g of isophorone diisocyanate and 0.7 g of aliphatic polyisocyanate based on hexamethylene diisocyanate (trade name: AE700-100, ASAHI KASEI) were added and reacted at 75 ° C. After confirming that the residual isocyanate groups were not removed by IR, the temperature was lowered to 50 캜 and 1 g of 2-methacryloyloxyethyl isocyanate (MOI) was added. After confirming that the isocyanate group remained in the IR group was maintained at 50 DEG C for 2 hours, a urethane (meth) acrylate copolymer was prepared.

Manufacturing example  2: urethane ( Meta ) Acrylate  Copolymer production

1 g of 2-methacryloyloxyethyl isocyanate (MOI) was added to the reaction mixture, and 1 g of 3-isocyanate propyltriethoxysilane was added thereto for 1 hour to confirm that the isocyanate group remaining in the IR group disappeared. , The same procedure as in Preparation Example 1 was carried out to prepare a urethane acrylate copolymer.

Manufacturing example  3: Urethane Acrylate  Copolymer production

In a 2 L four-necked flask, 89.45 g of polypropylene diol was initially charged, a reflux condenser on one side, a thermometer on the other side, and a dropping funnel on the other side. After the temperature of the flask solution was raised to 60 캜, 1.3 g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration was added to toluene. Subsequently, 9.15 g of isophorone diisocyanate and 0.7 g of hexamethylene diisocyanate cyclic trimer (HDI trimer, DESMODUR N-3300, Bayer) were added and reacted at 75 ° C. After the reaction for 3 hours, when the theoretical NCO% was reached, the temperature was lowered to 60 DEG C and then 3.37 g of 2-hydroxyethyl acrylate was added. After confirming that the isocyanate groups remaining in the IR group remained at 60 DEG C for 2 hours, a urethane acrylate polymer was prepared.

Manufacturing example  4: urethane Acrylate  Copolymer production

In a 2 L four-necked flask, 89.45 g of polypropylene diol was initially charged, a reflux condenser on one side, a thermometer on the other side, and a dropping funnel on the other side. After the temperature of the flask solution was raised to 60 캜, 1.3 g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration was added to toluene. Subsequently, 9.52 g of isophorone diisocyanate and 0.3 g of hexamethylene diisocyanate cyclic trimer (HDI trimer, DESMODUR N-3300, Bayer) were added and reacted at 75 ° C. After the reaction for 3 hours, when the theoretical NCO% was reached, the temperature was lowered to 60 DEG C and then 3.37 g of 2-hydroxyethyl acrylate was added. After confirming that the isocyanate groups remaining in the IR group remained at 60 DEG C for 2 hours, a urethane acrylate polymer was prepared.

Specific specifications of the components used in the following examples and comparative examples are as follows.

(A) urethane (meth) acrylate copolymer:

(A1) The urethane acrylate copolymer prepared in Production Example 1

(A2) The urethane acrylate copolymer prepared in Preparation Example 2

(A3) The urethane acrylate copolymer prepared in Preparation Example 3

(A4) The urethane acrylate copolymer prepared in Production Example 4

(B) reactive monomer:

(B1) 4-hydroxybutyl acrylate (4-HBA),

(B2) 2-hydroxyethyl methacrylate (2-HEMA),

(B3) isobornyl acrylate (IBXA),

(B4) acryloylmorpholine (ACMO),

(B5)? -Carboxyethyl acrylate (? -CEA),

(B6) Vinyltrimethoxysilane (A-171)

(C) Initiator:

(C1) Irgacure 184,

(C2) Irgacure 754

(D) Ultraviolet absorber Tinuvin 384-2

(E) Irganox 1010 was used as an antioxidant.

Example  1-4: Preparation of pressure-sensitive adhesive composition

Each component was mixed with the content (unit: parts by weight) shown in the following Table 1 and stirred for 1 hour or more to prepare a pressure-sensitive adhesive composition.

Comparative Example  1-2: Preparation of pressure-sensitive adhesive composition

Each component was mixed with the content (unit: parts by weight) shown in the following Table 1 and stirred for 1 hour or more to prepare a pressure-sensitive adhesive composition.

Example Comparative Example One 2 3 4 One 2 (A) (A1) 77 - - - - - (A2) - 77 57 87 - - (A3) - - - - 77 - (A4) - - - - - 77 (B) (B1) 3 3 13 One 3 3 (B2) One One 6 One One One (B3) 7 7 12 One 7 7 (B4) 2 2 2 2 2 2 (B5) 4 4 4 2 4 4 (B6) One One One One One One (C) (C1) 2 2 2 2 2 2 (C2) 2 2 2 2 2 2 (D) 0.9 0.9 0.9 0.9 0.9 0.9 (E) 0.1 0.1 0.1 0.1 0.1 0.1

Experimental Example : Measurement of physical properties

The following properties were measured for the optical pressure-sensitive adhesive compositions prepared in Examples and Comparative Examples, and the results are shown in Table 2 below.

&Lt; Method for measuring physical properties &

1. Elongation ratio: ASTM D638 is used to prepare and evaluate specimens. The optical pressure-sensitive adhesive composition is coated on the release PET film and cured at 3000 mJ / cm 2 to obtain an optical pressure-sensitive adhesive film having a thickness of 500 μm. Use the Instron series IX / s Automated materials Tester-3343 to measure the elongation at break of the specimen.

2. Tensile strength: The tensile strength is simultaneously measured in the elongation measurement.

3. Cure shrinkage: The specific gravity of the liquid optical adhesive composition before curing is measured. The pressure-sensitive adhesive composition is coated on a PET release film to a thickness of 200 mu m and cured to 3000 mJ / cm &lt; 2 &gt; to form an optical pressure-sensitive adhesive film having a thickness of 200 mu m. The release film was removed and the specific gravity was measured with a digital solid viscometer DME-220E (Shinko) for an optical adhesive agent film having a thickness of 200 mu m. The hardening shrinkage ratio is calculated according to the following formula (1).

<Formula 1>

Cure shrinkage ratio = [(specific gravity of liquid composition before curing-specific gravity of solid after curing)] / specific gravity of liquid composition before curing x 100

4. Adhesive force: The adhesion between the upper glass and the lower glass of the pressure-sensitive adhesive film made of the pressure-sensitive adhesive composition is measured. The size of the lower glass is 2cm x 2cm x 1mm, and the size of the upper glass is 1.5cm x 1.5cm x 1mm. The optical pressure-sensitive adhesive composition was coated on a lower glass, the upper glass was covered, and the pressure-sensitive adhesive composition was cured at 3000 mJ / cm 2 to prepare a pressure-sensitive adhesive film sample having a thickness of 200 μm. For the prepared sample, the force to peel the upper glass from the side is measured with a constant force of 200kgf at 25 ° C with the dage series 4000PXY, an adhesive force measuring instrument.

5. Plan view: Curing a 200 m thick optical adhesive composition applied between glass and glass to 3000 mJ / cm2. The degree of deformation of the glass was measured by measuring the flatness with a non - contact flat panel display. The lower the flatness, the less deformation.

6. Refractive index: Measured by the ASTM D1218 method. The pressure-sensitive adhesive composition was coated on the release PET film and cured at 3000 mJ / cm 2, to prepare a pressure-sensitive adhesive film having a thickness of 200 탆. The release film is removed and the refractive index is measured on a 200 탆 thick pressure sensitive adhesive film with an ABBE 5 (Bellingham / stanley Ltd) instrument.

7. Visible light transmittance: Coated on a release PET film and cured at 3000 mJ / cm2, to produce a 200 탆 thick pressure sensitive adhesive film. The release film is removed and measured on a 200 탆 thick pressure sensitive adhesive film in a 400-800 nm area with a Lambda 950 (perkin elmer) instrument.

Example Comparative Example One 2 3 4 One 2 Elongation (%) 710 700 700 400 190 280 Tensile strength (gf / mm2) 4 3 3 6 25 29 Cure shrinkage (%) 0.6 0.6 0.6 0.7 1.9 1.8 Adhesion (kgf) 49 50 51 49 34 42 Floor plan 0.0325 0.0355 0.0365 0.0389 0.1358 0.1478 Refractive index 1.47 1.47 1.47 1.47 1.47 1.47 Visible ray
Transmittance (%) 93 93 93 92 93 93

As can be seen from Table 2, the optical pressure-sensitive adhesive composition comprising the urethane (meth) acrylate copolymer of the present invention has low flatness and no warpage which was a conventional problem. On the other hand, a composition comprising a urethane acrylate copolymer prepared without an isocyanate of formula (1) and a composition comprising a urethane acrylate copolymer polymerized using a previously used HDI trimer has a high planarity See Example 1-2).

Claims (29)

Urethane (meth) acrylate copolymer, reactive A pressure-sensitive adhesive composition comprising a monomer and an initiator,
An elongation of 200-800%, and a tensile strength of 10 gf / mm ² or less.
The optical adhesive film according to claim 1, wherein the urethane (meth) acrylate copolymer contains a hydroxyl group and a vinyl group.
The optical adhesive film according to claim 1, wherein the tensile strength is 0.1 to 10 gf / mm ² .
The method of claim 1, wherein the urethane (meth) acrylate copolymer is a urethane polyol; And a copolymer obtained by copolymerizing a monomer having an isocyanate group and a vinyl group.
The optical pressure-sensitive adhesive film according to claim 4, wherein the urethane polyol contains a hydroxyl group.
The optical adhesive film according to claim 4, wherein the urethane polyol is a copolymer obtained by copolymerizing a polyol and an isocyanate compound. The optical adhesive film according to claim 6, wherein the isocyanate compound has a structure represented by the following formula (1).
&Lt; Formula 1 >

Wherein R1, R2 and R3 are independently of each other - (CH2) n- and n is an integer from 1-10.
8. The optical adhesive according to claim 7, wherein the isocyanate compound further comprises a biuret type, an isocyanurate type, an adduct type, and a diisocyanate compound. film.
The optical adhesive film according to claim 4, wherein the urethane (meth) acrylate copolymer is further polymerized with a monomer having a silane group and an isocyanate group.
A urethane (meth) acrylate-based copolymer obtained by copolymerizing a urethane polyol and a (meth) acrylic monomer having an isocyanate group and a vinyl group; Reactive monomers; And an initiator.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the urethane polyol contains a hydroxyl group.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the optical pressure-sensitive adhesive composition further comprises at least one selected from the group consisting of an ultraviolet absorber and an antioxidant.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the urethane polyol is a copolymer of a polyol and an isocyanate compound.
The optical pressure-sensitive adhesive composition according to claim 13, wherein the isocyanate compound has a structure represented by the following formula (1).
&Lt; Formula 1 >

Wherein R1, R2 and R3 are independently of each other - (CH2) n- and n is an integer from 1-10.
15. The method of claim 14, wherein the isocyanate compound further comprises a biuret type, an isocyanurate type, an adduct type, and a diisocyanate compound. Composition.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the urethane (meth) acrylate copolymer is contained in an amount of 35-93.45 wt% in the optical pressure-sensitive adhesive composition.
14. The method according to claim 10 or 13, wherein the copolymerization is a copolymerization of one species selected from the group consisting of dibutyltin dilaurate (DBTDL), triethylenediamine (TEDA), and 1,4-azabicyclo [2.2.2] Of the total weight of the composition.
The optical pressure-sensitive adhesive composition according to claim 17, wherein the catalyst is used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the isocyanate compound.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the urethane (meth) acrylate copolymer is further polymerized with a monomer having a silane group and an isocyanate group.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the optical pressure-sensitive adhesive composition further comprises a silane coupling agent.
14. The process according to claim 13, wherein the polyol is selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polytetramethylene glycol, tetramethylene glycol, 1,3-butanediol, Polypropylene glycol, neopentyl glycol, polycarbonate polyol, polyester polyol, and 1,4-cyclohexanedimethanol.
16. The process according to claim 15, wherein the diisocyanate compound is selected from the group consisting of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, hydrogenated diphenylmethane diisocyanate and naphthalene diisocyanate And at least one selected from the group consisting of a fluorine-containing polymer and a fluorine-containing polymer.
[Claim 10] The method according to claim 10, wherein the (meth) acrylic monomer having an isocyanate group and a vinyl group is at least one member selected from the group consisting of methacryloyloxyethyl isocyanate and 3-isocyanatopropyl (meth) acrylate By weight.
The optical pressure-sensitive adhesive composition according to claim 1 or 10, wherein the reactive monomer is a reactive (meth) acrylate monomer.
Section 1 or The reactive monomer according to claim 10, wherein the reactive monomer is selected from the group consisting of a (meth) acrylic acid ester having a hydroxyl group and an alkyl group having 2 to 20 carbon atoms, a (meth) acrylic acid ester having an alicyclic ring having 4 to 20 carbon atoms, nitrogen, (Meth) acrylic monomer having an alicyclic ring having 4 to 20 carbon atoms and containing at least one hetero atom selected from the group consisting of a (meth) acrylic monomer having a carboxyl group, and a monomer having a vinyl group and a silane group &Lt; / RTI &gt;
The optical pressure-sensitive adhesive composition according to claim 1 or 10, wherein the initiator is a photoinitiator.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the optical pressure-sensitive adhesive composition has a curing shrinkage of 1% or less.
The optical pressure-sensitive adhesive composition according to claim 10, wherein the viscosity of the optical pressure-sensitive adhesive composition is from 500 to 20,000 cps at 25 캜.
A display panel comprising an optical adhesive film formed by the optical adhesive film of any one of claims 1 to 9 or the optical adhesive composition of claim 10.

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