KR20120078589A - Optically adhesive composition, optically adhesive film prepared from the same, and display panel comprising the same - Google Patents

Abstract

PURPOSE: An optical adhesive film is provided to improve elongation and tensile strength, by comprising urethane (meth)acrylate copolymer having a hydroxy group and a vinyl group in terminal thereof, thereby capable being used as an optical adhesive film for display of medium to large sizes. CONSTITUTION: An optical adhesive film is formed by an adhesive composition comprising urethane (meth)acrylate copolymer, a reactive monomer, and an initiator, the elongation is 200-800%, the tensile strength is 10 gf/mm^2 or less. The urethane (meth)acrylate copolymer contains a hydroxy group, and a vinyl group. The urethane (meth)acrylate copolymer is polymerized of a urethane polyol, and a monomer having an isocyanate group and a vinyl group. The urethane polyol comprises a hydroxy group.

Description

Optical adhesive composition, an optical adhesive film formed therefrom and a display panel comprising the same {Optically adhesive composition, optically adhesive film prepared from the same, and display panel comprising the same}

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

Recently, with the development of electronic and communication related technologies, various electronic devices using a touch window device in which a touch panel and an LCD window panel are integrated are widely developed and spread. Conventionally, an optically clear adhesive film (OCA) was used between the window glass and the touch screen panel sensor glass. OCA film is used for interlayer bonding, which stacks components when making LCDs, or for attaching touch screens to mobile phones. OCA film transmits more than 97% of light and functions like glass, but also improves screen sharpness and adhesiveness compared to conventional double-sided tape.

However, with the development of various types of mobile phones, there are limitations on the use of OCA films, and the necessity of lowering the price of expensive OCA films is emerging. In addition, since the conventional OCA film has the inherent limitation of a solid transparent tape, bubbles may be generated due to the instantaneous air inflow even if the producer adheres to the interlayer surface between the window panel and the touch panel with elaborate efforts. .

In order to solve this problem, a method of replacing an OCA film using a resin-type liquid curable pressure-sensitive adhesive of a resin type, rather than a film type, is currently being devised.

An object of the present invention is to provide an optical pressure-sensitive adhesive composition that can solve the distortion problem after curing.

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

Still another object of the present invention is to provide a display panel including the optical pressure-sensitive adhesive composition.

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

In one embodiment, the urethane (meth) acrylate copolymer may be a copolymer obtained by copolymerizing a polyol, an isocyanate compound of Formula 1 below, 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 further polymerize monomers having silane groups and isocyanate groups.

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

The pressure-sensitive adhesive film of the present invention may be prepared by the optical pressure-sensitive adhesive composition.

The display panel of the present invention may include the optical adhesive composition.

The present invention solved the distortion problem in the optical pressure-sensitive adhesive film. The present invention provides an optical pressure-sensitive adhesive film that can be used as an optical pressure-sensitive adhesive film for displays of medium and large size.

1-3 shows the top view after the photocuring of the optical adhesive composition of Example 1, the comparative example 1, and the comparative example 2, respectively.

An optical pressure-sensitive adhesive composition of one aspect of the present invention includes a urethane (meth) acrylate copolymer, a reactive monomer and an initiator, when the film is formed after curing, the elongation may be 200-800%, the tensile strength is 10gf / mm2 or less have.

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

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

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

When the elongation is less than 200%, the pressure-sensitive adhesive layer tends to shrink after attaching two adherends. If the elongation is more than 800%, the coating is too soft and has a tack, which shows poor characteristics during rework.

If the tensile strength is more than 10gf / mm2, the strength of the coating film is so strong that the impact resistance of the display product is insufficient, the adhesion is also low.

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

The optical pressure-sensitive adhesive composition of the present invention can be used by applying or injecting the adhered portion to be adhered as a liquid form having a viscosity of 500-20,000 cps at 25 ° C. 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 hydroxyl group and a vinyl group are contained in the terminal of the said copolymer.

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

For example, the urethane (meth) acrylate copolymer is a first polymerization of the polyol and the isocyanate compound of Formula 1 to prepare a urethane polyol. Then, it can manufacture by superposing | polymerizing the (meth) acrylic-type monomer which has an isocyanate group and a vinyl group.

Urethane polyols have urethane bonds and hydroxyl groups. Urethane polyols are prepared by polymerizing an excess of a polyol with a relatively small amount of isocyanate compounds, and thus have a hydroxyl group terminus with a urethane bond.

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, whereby the urethane (meth) acrylate copolymer has a hydroxyl group and a vinyl group.

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

The urethane (meth) acrylate copolymer may be included at 35-93.45% by weight in the optical pressure-sensitive adhesive composition on a solids basis. Within this range, the main characteristics of the urethane binder are high elongation, low tensile strength, and low cure shrinkage. Preferably it may be included in 77-87% by weight.

In the production of the urethane (meth) acrylate copolymer, the equivalent ratio of the polyol, the isocyanate compound, and the (meth) acrylic monomer having an isocyanate group and a vinyl group can be appropriately adjusted. For example, the polyol: isocyanate compound: the (meth) acrylic monomer having an 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 characteristics of the urethane binder are high elongation, low tensile strength, and low cure shrinkage.

Polyols are 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 It may include, but is not limited to, one or more selected from the group consisting of polyester polyols and 1,4-cyclohexanedimethanol.

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

Specifically, the isocyanate compound may be an isocyanate compound (A) of Formula 1 below.

<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 may be purchased and used as a commercially available product (AE700-100, ASAHI KASEI).

In addition, the isocyanate compound may be a mixture of the isocyanate compound (A) of 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 member selected from the group consisting of a biuret type, an isocyanurate type, and an adduct type as follows. can do.

* Burette Type:

Isocyanurate type:

* Type of adduct:

(In the above, R1, R2, R3 are independently of each other-(CH2) n-, n is an integer of 1-20, R4 is hydrogen, alkyl group of 1-6 carbon atoms, alkoxy group of 1-6 carbon atoms or halogen )

In addition, the compound (B) having two or more isocyanate groups may include at least one member selected from the group consisting of ordinary diisocyanate compounds such as isoprene-based, hexamethylene-based and toluene-based compounds. Specifically, the diisocyanate compound is toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, hydrogenated diphenyl, including 2,4 or 2,6 toluene diisocyanate, etc. It may include one or more selected from the group consisting of 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 selected from the group consisting of 2- (meth) acryloyloxyethyl isocyanate (MOI) and 3-isocyanatopropyl (meth) acrylate. However, the present invention is 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 a conventional polymerization method 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 ° 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 using a catalyst to prepare the copolymer. The catalyst may be, for example, one or more selected from the group consisting of dibutyltin dilaurate (DBTDL), triethylene diamine (TEDA), 1,4-azabicyclo [2.2.2] octane, and the like, It is not limited to these. The catalyst may be used in 0.05 to 2 parts by weight based on 100 parts by weight of the isocyanate compound.

In the urethane (meth) acrylate copolymer, monomers having a silane group and an isocyanate group may be further polymerized. The monomer having a silane group binds to the hydroxyl group of the urethane (meth) acrylate copolymer. The monomer having the silane group and the isocyanate group may be, for example, 3-isocyanato propyltriethoxysilane, but is 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 can be a reactive (meth) acrylate monomer.

The reactive monomer may include at least one 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 monomer having a hydroxy group, a vinyl monomer having an alicyclic group among vinyl monomers having an alkyl group, a vinyl monomer having a carboxyl group, and a vinyl monomer having a vinyl group and a silane group. .

The reactive monomer may be included in an amount of 5-45% by weight in the optical pressure-sensitive adhesive composition on a solids basis. By adjusting the viscosity of the material within the above range to improve the workability, it can exhibit a low shrinkage value within the above range. Preferably, it may be included in 8-38% by weight.

The vinyl monomer having a hydroxyl group may be a (meth) acrylic acid ester having a hydroxyl group in the terminal or structure and having an alkyl group having 2 to 20 carbon atoms. For example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 6- Hydroxyhexyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1 , 6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth 1) selected from the group consisting of) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, and cyclohexane dimethanol mono (meth) acrylate Ideal But hamhal, but is not limited to these.

Vinyl-based monomer having a hydroxy group may be included in 1 to 25% by weight, preferably 2 to 19% by weight in the optical pressure-sensitive adhesive composition. The desired modulus can be obtained after curing within the above range.

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

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) having a heteroalicyclic ring containing nitrogen, oxygen or sulfur having 4 to 6 carbon atoms. It may include an acrylic monomer.

For example, the vinyl monomer having an alkyl group isobornyl (meth) acrylate, acryloyl morpholine, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, methyl (meth) acrylate, ethyl (Meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth ) Acrylates, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and lauryl (meth) acrylate It may mean one or more selected from the group consisting of, but is not limited to these.

Vinyl-based monomer having an alkyl group may be included in 1 to 20% by weight, preferably 3 to 14% by weight in the optical pressure-sensitive adhesive composition. It is easy to workability when coating in the above range, it is possible to obtain a result of low shrinkage rate when curing.

The vinyl monomer having a carboxyl group is, for example, a group consisting of β-carboxyethyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl acetic acid, (meth) acrylic acid, fumaric acid, maleic acid, and the like. It may mean one or more selected from, but is not limited thereto.

The vinyl monomer having a carboxyl group may be included in 1 to 10% by weight, preferably 3 to 5% by weight of the optical pressure-sensitive adhesive composition. Within this range, workability during coating is easy and low shrinkage results upon curing.

The vinyl monomer having a vinyl group and a silane group can increase the adhesion to glass. Such monomers include "(R1) (R2) (R3) Si- (CH2) m- (OOC) p-CH = CH2 (wherein R1, R2 and R3 are independently of each other hydrogen, halogen, 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 monomer having the vinyl group and the silane group may include at least one selected from the group consisting of vinyl trichlorosilane, vinyl trimethoxysilane, vinyl methyldimethoxysilane, and vinyl triethoxysilane. However, it is not limited thereto.

The monomer having a vinyl group and a silane group may be included in 1-20% by weight of the optical pressure-sensitive adhesive composition. Within this range, workability during coating is easy and low shrinkage results upon curing.

Initiator

The initiator can be used without limitation as long as it can exhibit excellent photoreaction in the ultraviolet wavelength range of 150nm-500nm. The initiator may comprise a photoinitiator.

The initiator may be, for example, one or more selected from the group consisting of acetophenone series, benzophenone series, triazine series, thioxanthone series, benzoin series or oxime series compounds, but is not limited thereto. For example, 1-hydroxycyclohexyl phenyl ketone, oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] -ethyl ester, benzophenone, 4-phenyl benzophenone, hydroxy benzophenone, acrylated 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, 2-phenyl-4,6-bis (trichloro Rhomethyl) -s-triazine, 2- (3 ', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, thioxanthone, 2-methylthioxanthone , Benzoin or benzoin methyl ether and the like can be used.

The initiator may be included in 1-20% by weight, preferably 5-8% by weight of the optical adhesive composition on a solids basis. Within the above range, the film after curing under UV exposure shows high elongation, low tensile strength and low shrinkage.

The optical pressure-sensitive adhesive composition of the present invention may further include one or more selected from the group consisting of ultraviolet absorbers and antioxidants.

Ultraviolet absorber

The ultraviolet absorber serves to improve the optical stability of the pressure-sensitive adhesive composition. The ultraviolet absorber may include one or more selected from the group consisting of benzotriazole-based, benzophenone-based and triazine-based, but is not limited thereto. For example, the ultraviolet absorber is a 7-linear or branched alkyl of 7 to 9 carbon atoms of 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) 4-hydroxybenzene propanoic acid. Ester, 2- (benzotriazol-2-yl) -4- (2,4,4-trimethylpentan-2-yl) phenol, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butyl Phenyl) benzotriazole, 2,4-hydroxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,4 -Diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxyphenyl)- 1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine or 2,4-diphenyl-6- ( 2-hydroxy-4-butoxyphenyl) -1,3,5-triazine and the like can be used.

UV absorbers may be included in 0.1-5% by weight, preferably 0.1-1% by weight of the optical pressure-sensitive adhesive composition on a solids basis. It is possible to prevent the yellowing of the surface of the film after curing within the above range.

Antioxidant

Antioxidant serves to prevent oxidation of the pressure-sensitive adhesive composition to improve thermal stability. The antioxidant may include, but is not limited to, one or more selected from the group consisting of phenolic compounds, quinone compounds, amine compounds, and phosphite compounds. For example, antioxidants include pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), tris (2,4-di-tert-butylphenyl ) Phosphite and the like.

Antioxidant may be included as 0.01-5% by weight, preferably 0.01-1% by weight in the optical adhesive composition on a solids basis. It prevents the aging of the film after curing within the above range, and shows excellent thermal stability.

The optical pressure-sensitive adhesive composition may further include a silane coupling agent to improve adhesion to the window glass.

The silane coupling agent can use what is known as a normal silane coupling agent, For example, the silane coupling agent containing a vinyl group or a mercapto group can be used. For example, polymeric fluorine-containing silicon compounds, such as a trimethoxy silane, a vinyl triethoxy silane, and (meth) acryloxy propyl trimethoxysilane; Silicon compounds having an epoxy structure, such as 3-glycidoxy propyl trimethoxysilane, 3-glycidoxy propylmethyl dimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane; Amino group-containing silicon compounds such as 3-aminopropyl trimethoxysilane, N- (2-aminoethyl) -3-aminopropyl trimethoxysilane, N- (2-aminoethyl) -3-aminopropyl methyl dimethoxysilane ; And 3-chloro propyl trimethoxysilane and the like may include one or more selected from the group consisting of, but is not limited thereto.

The silane coupling agent may be included in an amount of 0.1-6 parts by weight, preferably 0.1-3 parts by weight, based on 100 parts by weight of the optical adhesive composition. It exhibits excellent adhesion upon glass and adhesion within this range.

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

Curing shrinkage measures the specific gravity of the liquid composition before curing the optical pressure-sensitive adhesive composition. An optical pressure-sensitive adhesive composition is coated on a release film containing PET (polyethylene terephthalate) and cured at 3000-5000 mJ / cm 2 to prepare a 200 μm thick optical pressure-sensitive adhesive film. The release film is removed and specific gravity is measured for the optical pressure-sensitive adhesive film having a thickness of 200 μm. Hardening shrinkage is calculated | required according to following formula 1.

<Equation 1>

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

Preferably, the cure shrinkage may be 0.1-0.7%.

By increasing the elongation, lowering the tensile strength, and lowering the curing shrinkage, the optical pressure-sensitive adhesive composition can solve the warpage problem that has been a problem after photocuring in the conventional non-mobile display of medium and large size.

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

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

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. 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.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Manufacturing example  1: Urethane ( Meta ) Acrylate  Copolymer production

Into a 2 L four-necked flask, 80 g of polypropylenediol and 10 g of 1,4-butanediol were added first, a reflux condenser on one side, a thermometer on the other, and a dropping funnel on the other. After raising the temperature of the flask solution to 60 ℃, 1.3g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration in toluene was added. 6 g of isophorone diisocyanate and 0.7 g of Aliphatic polyisocyanate based on hexamethylene diisocyanate (trade name: AE700-100, ASAHI KASEI) were sequentially added and reacted at 75 ° C. After confirming that the isocyanate group remaining in the IR group disappeared, the temperature was lowered to 50 ° C., and 1 g of 2-methacryloyloxyethyl isocyanate (MOI) was added thereto. The urethane (meth) acrylate copolymer was produced by confirming that the isocyanate group which remains with an IR group disappears after hold | maintaining at 50 degreeC for 2 hours.

Manufacturing example  2: urethane ( Meta ) Acrylate  Copolymer production

After adding 1 g of 2-methacryloyloxyethyl isocyanate (MOI) in Preparation Example 1, it was confirmed that the isocyanate group remaining in the IR group disappeared, and 1 g of 3-isocyanatepropyltriethoxysilane was added and reacted for 1 hour. Except that was prepared in the same manner as in Preparation Example 1 to prepare a urethane acrylate copolymer.

Manufacturing example  3: urethane Acrylate  Copolymer production

89.45 g of polypropylenediol was first introduced into a 2 L four-necked flask, followed by a reflux condenser on one side, a thermometer on the other, and a dropping funnel on the other. After raising the temperature of the flask solution to 60 ℃, 1.3g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration in toluene was added. 9.15 g of isophorone diisocyanate and 0.7 g of hexamethylene diisocyanate cyclic trimer (HDI trimer, DESMODUR N-3300, Bayer) were sequentially added and reacted at 75 ° C. When the theoretical NCO% was reached after 3 hours of reaction, the temperature was lowered to 60 ° C., and 3.37 g of 2-hydroxyethyl acrylate was added thereto. The urethane acrylate polymer was prepared by confirming that the isocyanate group remaining in the IR group disappeared after holding at 60 ° C. for 2 hours.

Manufacturing example  4: urethane Acrylate  Copolymer production

89.45 g of polypropylenediol was first introduced into a 2 L four-necked flask, followed by a reflux condenser on one side, a thermometer on the other, and a dropping funnel on the other. After raising the temperature of the flask solution to 60 ℃, 1.3g of DBTDL (dibutyltin dilaurate) diluted to 10% concentration in toluene was added. 9.52 g of isophorone diisocyanate and 0.3 g of hexamethylene diisocyanate cyclic trimer (HDI trimer, DESMODUR N-3300, Bayer) were sequentially added and reacted at 75 ° C. When the theoretical NCO% was reached after 3 hours of reaction, the temperature was lowered to 60 ° C., and 3.37 g of 2-hydroxyethyl acrylate was added thereto. The urethane acrylate polymer was prepared by confirming that the isocyanate group remaining in the IR group disappeared after holding at 60 ° C. for 2 hours.

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

(A) urethane (meth) acrylate copolymer:

(A1) urethane acrylate copolymer prepared in Production Example 1

(A2) Urethane Acrylate Copolymer Prepared in Production Example 2

(A3) urethane acrylate copolymer prepared in Preparation Example 3

(A4) urethane acrylate copolymer prepared in Production Example 4

(B) reactive monomers:

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

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

(B3) isobornyl acrylate (IBXA),

(B4) acryloyl morpholine (ACMO),

(B5) β-carboxyethyl acrylate (β-CEA),

(B6) vinyl trimethoxysilane (A-171)

(C) Initiator:

(C1) Irgacure 184,

(C2) Irgacure 754

Tinuvin 384-2 as ultraviolet absorbent

Irganox 1010 was used as antioxidant (E).

Example  1-4: Preparation of Adhesive Composition

To the ingredients (unit: parts by weight) described in Table 1 below, the components were mixed and stirred for 1 hour or more to prepare a pressure-sensitive adhesive composition.

Comparative example  1-2: Preparation of Adhesive Composition

To the ingredients (unit: parts by weight) described in Table 1 below, the components were mixed 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 Property measurement

The physical properties of the optical adhesive compositions prepared in Examples and Comparative Examples were measured, and the results are shown in Table 2 below.

<Measurement method of physical property>

Elongation: Test and prepare specimens using the ASTM D638 method. The optical pressure-sensitive adhesive composition is coated on a release PET film and cured at 3000 mJ / cm 2 to obtain a 500 μm-thick optical pressure-sensitive adhesive film. Measure the elongation at break of the specimen using the Instron series IX / s Automated Materials Tester-3343.

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

3. Hardening shrinkage rate: Specific gravity is measured before hardening with respect to a liquid optical adhesive composition. The pressure-sensitive adhesive composition is coated on a PET release film to a thickness of 200 μm and cured at 3000 mJ / cm 2 to form an optical pressure-sensitive adhesive film having a thickness of 200 μm. The release film was removed, and specific gravity was measured with a digital solid-state hydrometer DME-220E (Shinko) on a 200 μm-thick optical adhesive film. The hardening shrinkage is calculated according to the following formula (1).

<Equation 1>

Cure shrinkage = [(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 adhesive force 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 bottom glass is 2cm x 2cm x 1mm, and the size of the top glass is 1.5cm x 1.5cm x 1mm. The optical pressure-sensitive adhesive composition is coated on the lower glass, the upper glass is covered, and cured at 3000 mJ / cm 2, thereby preparing a pressure-sensitive adhesive film sample having a thickness of 200 μm. For the prepared samples, the force of peeling the upper glass was pushed from the side with a constant force of 200 kgf at 25 ° C. with a dage series 4000 PXY, which is an adhesive force measuring instrument.

5. Top View: The 200 μm thick optical pressure sensitive adhesive composition applied between the glass and the glass is cured at 3000 mJ / cm 2. The degree of deformation of the glass was measured by measuring a plan view with a non-contact flat panel display. Lower plan views indicate less strain.

6. Refractive index: Measured by ASTM D1218 method. After coating the pressure-sensitive adhesive composition on the release PET film and cured to 3000mJ / cm 2 to prepare a pressure-sensitive adhesive film of 200㎛ thickness. The release film is removed and the refractive index is measured with an ABBE5 (Bellingham / stanley Ltd) instrument for a 200 μm thick adhesive film.

7. Visible light transmittance: A pressure-sensitive adhesive film having a thickness of 200 μm is prepared after coating on a release PET film and curing at 3000 mJ / cm 2. The release film is removed and measured on a 400-800 nm region with a Lambda 950 (perkin elmer) instrument for a 200 μm thick adhesive film.

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 Hardening Shrinkage (%) 0.6 0.6 0.6 0.7 1.9 1.8 Adhesive force (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 light
Transmittance (%) 93 93 93 92 93 93

As shown in Table 2, the optical pressure-sensitive adhesive composition containing the urethane (meth) acrylate copolymer of the present invention can be seen that there is no warpage that has been a conventional problem because of low planarity. On the other hand, it can be seen that the composition comprising the urethane acrylate copolymer prepared without the isocyanate of formula 1 and the composition including the urethane acrylate copolymer polymerized using the HDI trimer used in the past (high comparison) See Example 1-2).

Claims (29)

Urethane (meth) acrylate copolymer, reactive It is formed of a pressure-sensitive adhesive composition comprising a monomer and an initiator,
An optical adhesive film having an elongation of 200-800% and a tensile strength of 10 gf / mm ² or less.
The optical pressure-sensitive adhesive film according to claim 1, wherein the urethane (meth) acrylate copolymer contains a hydroxyl group and a vinyl group.
The optical pressure-sensitive adhesive film of 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 urethane polyol; And it is a copolymer which copolymerized the monomer which has an isocyanate group and a vinyl group, The optical adhesive film characterized by the above-mentioned.
The optical pressure-sensitive adhesive film of claim 4, wherein the urethane polyol contains a hydroxyl group.
The optical pressure-sensitive adhesive film of claim 4, wherein the urethane polyol is a copolymer obtained by copolymerizing a polyol and an isocyanate compound. The optical pressure-sensitive adhesive film of claim 6, wherein the isocyanate compound has a structure represented by the following Chemical 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 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 pressure-sensitive adhesive film of claim 4, wherein the urethane (meth) acrylate copolymer is further polymerized with a monomer having a silane group and an isocyanate group.
Urethane (meth) acrylate copolymers 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 of claim 10, wherein the optical pressure-sensitive adhesive composition further comprises at least one member selected from the group consisting of ultraviolet absorbers and antioxidants.
The optical pressure-sensitive adhesive composition of claim 10, wherein the urethane polyol is a copolymer of a polyol and an isocyanate compound.
The optical pressure-sensitive adhesive composition of claim 13, wherein the isocyanate compound has a structure represented by the following Chemical Formula 1.
<Formula 1>

(Wherein R1, R2 and R3 are independently of each other-(CH2) n- and n is an integer from 1-10).
15. The optical pressure sensitive adhesive 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 of claim 10, wherein the urethane (meth) acrylate copolymer is included in an amount of 35-93.45% by weight in the optical pressure-sensitive adhesive composition.
The method of claim 10 or 13, wherein the copolymerization is one selected from the group consisting of dibutyltin dilaurate (DBTDL), triethylene diamine (TEDA), 1,4-azabicyclo [2.2.2] octane. Optical adhesive composition, characterized in that carried out in the presence of the above catalyst.
The optical pressure-sensitive adhesive composition of 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 of 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 of claim 10, wherein the optical pressure-sensitive adhesive composition further comprises a silane coupling agent.
The method of claim 13, wherein the polyol is 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-cyclohexane dimethanol is at least one member selected from the group consisting of an optical pressure-sensitive adhesive composition.
The diisocyanate compound 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. Optical pressure-sensitive adhesive composition, characterized in that at least one selected.
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. An optical pressure-sensitive adhesive composition.
The optical pressure sensitive adhesive composition according to claim 1 or 10, wherein the reactive monomer is a reactive (meth) acrylate monomer.
Claim 1 or The group of claim 10, wherein the reactive monomer is a group consisting of a (meth) acrylic acid ester having a hydroxy 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, oxygen, and sulfur At least one member selected from the group consisting of (meth) acrylic monomers having 4 to 20 carbon alicyclic rings, at least one hetero atom selected from (meth) acrylic monomers having carboxyl groups, and monomers having vinyl groups and silane groups Optical adhesive composition, characterized in that.
The optical pressure sensitive adhesive composition according to claim 1 or 10, wherein the initiator is a photoinitiator.
The optical pressure-sensitive adhesive composition of claim 10, wherein the optical pressure-sensitive adhesive composition has a cure shrinkage of 1% or less.
The optical pressure-sensitive adhesive composition of claim 10, wherein the optical pressure-sensitive adhesive composition has a viscosity of 500-20,000 cps at 25 ° C.
A display panel comprising the optical pressure-sensitive adhesive film of any one of claims 1 to 9 or the optical pressure-sensitive adhesive film formed of the optical pressure-sensitive adhesive composition of claim 10.

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