KR101459124B1 - Photo-curable adhesive composition and display device comprising the same - Google Patents

Abstract

The present invention relates to a photocurable pressure-sensitive adhesive composition. The photocurable pressure-sensitive adhesive composition includes a urethane (meth) acrylate resin, a hydroxyl group-containing polybutadiene, a photocurable monomer, and a photoinitiator. The photocurable pressure-sensitive adhesive composition has good outdoor visibility, excellent impact strength and light transmittance, and minimizes the occurrence of a high shrinkage ratio during photo-curing, so that it can be suitably used for a display.

Description

TECHNICAL FIELD [0001] The present invention relates to a photocurable pressure-sensitive adhesive composition and a display device including the same.

The present invention relates to a photocurable pressure-sensitive adhesive composition and a display device comprising the same. More specifically, the present invention relates to a photo-curable pressure-sensitive adhesive composition which improves outdoor visibility and shrinkage by incorporating a specific binder, and is excellent in light transmittance and impact resistance, and a display device including the same.

Mobile displays can be divided into mobile display, non-mobile TV and monitor display. The main development objective in such a display panel is to improve the outdoor visibility and to enhance the impact strength by compensating for the weak point of the impact due to the enlargement of the panel. Thus, it is the optical adhesive film which improves the outdoor visibility and plays the role of impact reinforcement.

The display panel has a glass window layer at the outermost portion, an air layer at the bottom of the window layer, and an ITO glass at the bottom of the air layer. The air layer is filled with a transparent material having a refractive index similar to that of the window glass to improve outdoor visibility.

Materials currently used as optical adhesives are classified into liquid type and film type materials. The film-type material is convenient to use but is difficult to apply to various structural forms, and it is difficult to remove bubbles generated when attaching to a substrate. Also, it has a disadvantage that it is difficult to remove due to high internal cohesive force, and the re-work characteristic is bad, and the manufacturing process of the film is complicated and expensive. Recently, there has been a tendency to develop liquid materials which are easy to remove air bubbles and are cheap in price. Such a liquid material forms a film through photocuring. The liquid type adhesive is cured with heat or light energy in the state of being filled in the substrate and applied to the film. However, the liquid type is relatively easy to remove bubbles, but has a high shrinkage ratio upon photo-curing. Also, the liquid-phase pressure-sensitive adhesive composition developed so far has a pH of less than 4 and a high acidity, which causes corrosion on the substrate.

An object of the present invention is to provide a photocurable pressure-sensitive adhesive composition capable of securing good outdoor visibility and having a pH of 4 or more to minimize substrate corrosion, and a display device including the same.

Another object of the present invention is to provide a photocurable pressure-sensitive adhesive composition which improves the impact by compensating for weak points due to the enlargement of the panel, and a display device including the same.

Another object of the present invention is to provide a photo-curable pressure-sensitive adhesive composition which minimizes the occurrence of a high shrinkage rate upon photo-curing and has an excellent elongation, and a display device containing the same.

Still another object of the present invention is to provide a photocurable pressure-sensitive adhesive composition having excellent light transmittance and adhesion, and a display device including the same.

Another object of the present invention is to provide a photocurable pressure-sensitive adhesive composition having excellent tensile strength, impact strength, refractive index, appearance after curing, and liquid spreadability, and a display device containing the same.

One aspect of the present invention relates to a photocurable pressure-sensitive adhesive composition. In one embodiment, the photocurable pressure sensitive adhesive composition comprises a urethane (meth) acrylate resin, a hydroxyl group-containing polybutadiene, a photocurable monomer, and a photoinitiator.

In another embodiment, the photocurable pressure-sensitive adhesive composition comprises a urethane (meth) acrylate resin and a hydroxyl group-containing polybutadiene, and is characterized by having a pH of 4 or more.

In another embodiment, the photocurable pressure-sensitive adhesive composition comprises a urethane (meth) acrylate resin and a hydroxyl group-containing polybutadiene, and has a hardening shrinkage of 3% or less and an elongation of 200 to 800% according to ASTM D638 do.

The photocurable pressure sensitive adhesive composition may comprise 35 to 75% by weight of a urethane (meth) acrylate resin, 5 to 30% by weight of a hydroxyl group-containing polybutadiene, 15 to 40% by weight of a photocurable monomer, and 1 to 5% by weight of a photoinitiator have.

In an embodiment, the weight ratio between the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene may be 70:30 to 95: 5.

In an embodiment, the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene may be 50 to 80% by weight of the total pressure-sensitive adhesive composition.

The urethane (meth) acrylate resin may contain a vinyl group at the terminal. The urethane (meth) acrylate resin may have a weight average molecular weight of 15,000 to 20,000 g / mol and a polydispersity of 1 to 3. The urethane (meth) acrylate resin may have a glass transition temperature of -65 to -55 캜 and a viscosity at 25 캜 of 25,000 to 35,000 cps.

In the specific examples, the hydroxyl group-containing polybutadiene may have a weight average molecular weight of 1,500 to 3,000 g / mol and a polydispersity of 1.2 to 2.2. The hydroxyl group-containing polybutadiene may have a hydroxy value of 1.7 to 1.9 meq / g and a butadiene group content of 70% or more. The hydroxyl group-containing polybutadiene may have a glass transition temperature of -80 to -70 占 폚.

The hydroxyl group-containing polybutadiene may have a vinyl group at the terminal.

The hydroxyl group-containing polybutadiene may have a structure represented by the following formula (1).

[Chemical Formula 1]

(Where x is 0.1 to 0.35, y is 0.1 to 0.35, and z is 0.4 to 0.7).

(Meth) acrylate having a hydroxyl group, a (meth) acrylate having a monocyclic or heterocyclic alicyclic ring, a (meth) acrylate having a single alicyclic heterocycle having a nitrogen, oxygen, or sulfur, Acrylic monomer, a (meth) acrylic monomer having a carboxyl group, and a monomer having a vinyl group and a silane group.

The photocurable pressure-sensitive adhesive composition may further include additives such as a silane coupling agent, an ultraviolet absorber, and a heat stabilizer. These additives may be used singly or in combination.

The photocurable pressure-sensitive adhesive composition may have a modulus of 10 kPa to 50 kPa.

Another aspect of the present invention relates to a display device comprising the photocurable pressure-sensitive adhesive composition.

The present invention has the advantages of securing good outdoor visibility and minimizing substrate corrosion due to the pH of 4 or more, improving the impact by compensating for the weak point due to the enlargement of the panel, and causing a high shrinkage rate upon photocuring The present invention provides a photo-curable pressure-sensitive adhesive composition which is minimized and has excellent elongation, excellent in light transmittance and adhesion, excellent in tensile strength, refractive index, appearance after curing, and liquid spreadability, and a display device comprising the same.

The photocurable pressure-sensitive adhesive composition of the present invention comprises a urethane (meth) acrylate resin, a hydroxyl group-containing polybutadiene, a photo-curable monomer and a photoinitiator.

urethane ( Meta ) Acrylate  Suzy

The urethane (meth) acrylate resin of the present invention contains a vinyl group at the terminal. By including the vinyl group in this way, it participates in curing and has excellent modulus. In an embodiment, the vinyl group may contain 0.5 to 4 mol%, preferably 0.5 to 1.5 mol%, of the urethane (meth) acrylate resin. It is possible to maintain an excellent adhesive force within the above range and to reduce the aging process time.

In one embodiment, the urethane (meth) acrylate resin is a urethane polyol; 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 compound.

For example, the urethane (meth) acrylate resin may be a copolymer obtained by first polymerizing a polyol and an isocyanate compound to prepare a urethane polyol, and then polymerizing a (meth) acrylic monomer having an isocyanate group and a vinyl group. In an embodiment, the polyol: isocyanate compound: isocyanate group and (meth) acrylic monomer having a vinyl group can 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, But are not limited to, at least one selected from the group consisting of polyols, polyester polyols and 1,4-cyclohexane dimethanol.

The isocyanate compound is preferably a compound having at least two isocyanate groups. The diisocyanate compound may include, but is not limited to, at least one selected from the group consisting of isoprene, hexamethylene, and toluene compounds. For example, the diisocyanate compound may be selected from the group consisting of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and 2 , 4-toluene diisocyanate, and the like. In addition, it includes at least one member selected from the group consisting of biuret type, isocyanurate type, adduct type, and bifunctional prepolymer type But are not limited to these.

In another embodiment, the urethane (meth) acrylate resin may be polymerized from a monomer mixture comprising an isocyanate group containing (meth) acrylate and a hydroxyl group containing (meth) acrylate.

Examples of the isocyanate group-containing (meth) acrylate include 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 2-isocyanate propyl acrylate, 2- 1-methylpropylideneamino] carboxyamino) ethyl methacrylate), 2-isocyanatoethyl 2-propenoate (2-Isocyanatoethyl 2-propenoate And 1,1-bis (acryloyloxy methyl ethyl isocyanate), which may be used alone or in admixture of two or more. Of these, preferably, 2 (meth) acryloyloxyethyl isocyanate -Isocyanatoethyl methacrylate, and 2-isocyanatoethyl acrylate. The isocyanate group-containing (meth) acrylate In the above range, it is possible to maintain the adhesive strength over a certain level even after photo-curing and to increase the internal cohesion of the adhesive film to improve the modulus of the film. .

Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- hydroxypropyl (meth) Cyclohexanedimethanol mono (meth) acrylate, chloro-2-hydroxypropyl acrylate, diethylene glycol mono (meth) acrylate, (Meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentylglycol mono (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy- Phenyloxypropyl (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 2-hydroxyethylacrylamide and cyclohexane dimethanol monoacrylate, which may be used alone or in admixture of two or more. have. Further, compounds obtained by addition reaction of (meth) acrylic acid with a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether, glycidyl (meth) acrylate, etc. . Of these, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl acrylamide and cyclohexane dimethanol monoacrylate are preferable, Hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 2-hydroxyethylacrylamide are more preferable, and 2-hydroxyethyl acrylate and 2-hydroxyethyl acrylamide are particularly preferable. The hydroxyl group-containing (meth) acrylate may be contained in an amount of 0 to 10% by weight of the total monomer components. Preferably 1 to 5% by weight, and more preferably 1 to 4% by weight. In the above range, after reacting with the monomer having vinyl group, the remaining hydroxy group is minimized by reacting with the isocyanate curing agent to minimize the change with time due to the hydroxy group after attachment to the substrate.

In one embodiment, the urethane (meth) acrylate resin may have the structure of Formula 2:

(2)

(Wherein R 1, R 2 and R 3 are, independently of each other, a substituted or unsubstituted alkylene having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene having 5 to 20 carbon atoms, a substituted or unsubstituted 6 to 20 carbon atom And Y is a methyl group or a hydrogen atom).

The urethane (meth) acrylate resin may have a weight average molecular weight of 15,000 to 25,000 g / mol. In addition to being easy to polymerize within the above range, the flexibility of the coating film can be obtained even when a small amount of the curing agent is used, the reaction time can be minimized, and the shrinkage ratio is excellent.

The urethane (meth) acrylate resin may have a polydispersity of 1 to 3. In this range, since the molecular weight distribution of the binder is constant and the variation in production batch is small, the reproducibility is excellent and the physical properties of the final product are uniform.

The urethane (meth) acrylate resin may have a glass transition temperature of -65 to -55 占 폚 and a viscosity at 25 占 폚 of 25,000 to 45,000 cps. Within the above range, it is possible to provide a high adhesive force and excellent film forming ability after photo-curing and to provide excellent heat resistance.

In another embodiment, the urethane (meth) acrylate resin may not contain a hydroxy group. In this case, the viscosity of the binder can be lowered and can be preferably applied to a large display.

In the present invention, the urethane (meth) acrylate resin may be contained in an amount of 35 to 75% by weight in the photocurable pressure-sensitive adhesive composition based on the solid content. Outdoor visibility can be improved within the above range, and high elongation, low tensile strength and low curing shrinkage are exhibited. Preferably 40 to 70% by weight.

Hydroxyl group  contain Polybutadiene

The hydroxyl group-containing polybutadiene of the present invention is a polybutadiene having a hydroxy group at the terminal thereof, which controls the shrinkage ratio after photo-curing, has excellent film-forming ability, and is excellent in heat and light stability. Preferably, the hydroxyl group-containing polybutadiene has an excellent modulus and shrinkage by allowing the vinyl group to be present at the terminal or side chain to participate in curing.

In the specific examples, the hydroxyl group-containing polybutadiene may have a weight average molecular weight of 1,500 to 3,000 g / mol and a polydispersity of 1.2 to 2.2. In the above range, the photo-cured film has an advantage that the modulus can be kept low.

The hydroxyl group-containing polybutadiene may have a hydroxy value of 1.7 to 1.9 meq / g. In the above range, compatibility with acrylic monomers is excellent.

In an embodiment, the hydroxyl group-containing polybutadiene may have a butadiene group content of 70% or more, preferably 75 to 95%. The heat resistance is excellent in the above range.

The hydroxyl group-containing polybutadiene may have a glass transition temperature of -80 to -70 占 폚. The low modulus is maintained in the above range, and the impact characteristics and the like are good.

In one embodiment, the hydroxyl group-containing polybutadiene may have the structure of the following formula (1).

[Chemical Formula 1]

(Where x is 0.1 to 0.35, y is 0.1 to 0.35, and z is 0.4 to 0.7).

In the present invention, the hydroxyl group-containing polybutadiene may be contained in an amount of 5 to 30% by weight based on the solid content of the photocurable pressure-sensitive adhesive composition. Has a low shrinkage ratio within the above range, and can have an adhesive force and an excellent balance. And preferably 5 to 25% by weight.

In an embodiment, the weight ratio between the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene may be 70:30 to 95: 5. In this range, a low shrinkage ratio can be obtained, and excellent adhesive force characteristics can be obtained.

In an embodiment, the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene may be 50 to 80% by weight of the total pressure-sensitive adhesive composition. There is an advantage of having low modulus properties after photo-curing in the above range.

Light-curing type Monomer

The photocurable monomers used in the present invention include vinyl monomers having a hydroxy group, vinyl monomers having a carboxyl group, vinyl monomers having an alicyclic group, vinyl monomers having an alkyl group, (meth) acrylic monomers having an alicyclic heterocyclic ring, Monomers having a vinyl group and a silane group, and the like can be used. (Meth) acrylate having a hydroxy group, a (meth) acrylate having a monocyclic or heterocyclic alicyclic ring, a (meth) acrylic monomer having a monocyclic alicyclic heterocycle having a nitrogen, oxygen or sulfur , A (meth) acrylic monomer having a carboxyl group, and a monomer having a vinyl group and a silane group. (Meth) acrylate having a hydroxyl group and having an alkyl group of 2 to 10 carbon atoms, (meth) acrylate having a heterocyclic alicyclic ring of 10 to 20 carbon atoms, nitrogen of 4 to 6 carbon atoms, oxygen or sulfur (Meth) acrylic monomer having a single alicyclic heterocycle having a single ring, a carboxyl group-containing (meth) acrylic monomer and a monomer having a vinyl group and a silane group, and the like.

The vinyl-based monomer having a hydroxy group is not particularly limited as long as it is a monomer having a hydroxy group and a carbon-carbon double bond. The monomer may have at least one hydroxyl group, and the hydroxyl group may be at the end of the monomer or inside the structure. Examples of the vinyl monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- (Meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, Acrylate, neopentyl glycol mono (meth) acrylate, trimethylol (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta Hydroxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Roxy-3-phenyloxy (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, cyclohexane dimethanol mono (meth) acrylate, and the like. These vinyl monomers having a hydroxy group may be used singly or in combination of two or more. The monomer having a hydroxyl group may be contained in an amount of 1-20% by weight, or 1-15% by weight of the reactive monomer. Within the above range, a desired modulus can be obtained after curing.

The monomer having an alkyl group may be a (meth) acrylic acid ester having 1 to 20 carbon atoms which is cyclic or a linear or branched alkyl group, or a (meth) acrylic acid ester having a cycloaliphatic ring of a single ring or a heterocyclic ring of carbon number C4- . ≪ / RTI > The monomer having an alicyclic ring may be an acrylic monomer having a monocyclic or heterocyclic alicyclic ring containing a hetero atom such as nitrogen, oxygen, sulfur and the like. (Meth) acrylic acid ester having a heterocyclic alicyclic ring having 6 to 20 carbon atoms and an acrylic monomer having a single-ring heteroalicyclic ring containing a nitrogen, oxygen, sulfur or the like and having a carbon number of C4 to C6 . (Meth) acrylates such as isobornyl (meth) acrylate, acryloylmorpholine, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, methyl methacrylate, ethyl acrylate, styrene, (Meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, iso- (Meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, (Meth) acrylate, but are not limited thereto. The monomer having an alkyl group may be contained in an amount of 2 to 20% by weight, or 2 to 17% by weight, of the reactive monomer. Within the above range, workability during coating is easy and a low shrinkage ratio can be obtained when cured.

The monomer having a carboxyl group is, for example, a group composed of? -Carboxyethyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl acetic acid, acrylic acid, methacrylic acid, fumaric acid, , But is not limited thereto. The monomer having a carboxyl group may be contained in an amount of 1-6 wt%, or 1-5 wt% of the reactive monomer. Within the above range, workability in coating is easy and a low shrinkage ratio can be obtained in curing.

The monomer having a vinyl group and a silane group can increase adhesion to glass. Examples of such monomers include "(R1) (R2) (R3) Si- (CH2) n- COO-CH.dbd.CH2 where R1, R2 and R3 are independently hydrogen, halogen, And n is an integer of 0 to 10.) ". For example, the monomer may include at least one selected from the group consisting of vinyltrichlorosilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, and vinyltriethoxysilane, but 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, or 2-15% by weight of the reactive monomer. Within the above range, workability in coating is easy and a low shrinkage ratio can be obtained in curing.

The photocurable monomer may be contained in 15 to 40% by weight of the photocurable pressure-sensitive adhesive composition. Within the above-mentioned range, curing is effectively effected upon photo-curing and viscosity control of the photo-curable material is facilitated. Preferably 20 to 38% by weight.

Photoinitiator

The photoinitiator may be at least one selected from the group consisting of benzophenone, acetophenone, triazine, thioxanthone, benzoin, and oxime compounds, but is not limited thereto. For example, benzophenone, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) , 4'-bis (dimethylamino) benzophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy- (Trichloromethyl) -s-triazine, 2- (3 ', 4'-dimethoxystyryl) -4,6-bis (trichloro 2-methylthioxanthone, benzoin or benzoin methyl ether, and the like can be used.

The photoinitiator may be included in an amount of 1 to 5% by weight of the photocurable pressure-sensitive adhesive composition. Within the above range, the photo-curing is smoothly performed, and the viscosity of the photo-curable material is prevented from rising. Preferably 1.5 to 4.5% by weight.

The photocurable pressure-sensitive adhesive composition of the present invention may further contain additives such as a silane coupling agent, an ultraviolet absorber and a heat stabilizer. These additives may be used singly or in combination.

The ultraviolet absorber serves to improve 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 2- (benzotriazol-2-yl) -4- (2,4,4-trimethylpentan-2-yl) phenol, 2- (2'- Methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-bis (?,? - dimethylbenzyl) Di-t-butylphenyl) benzotriazole, 2,4-hydroxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone, 2,4-hydroxy-4-methoxybenzophenone- -Sulfonic acid, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4- 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. The ultraviolet absorber may be contained in an amount of 0.1 to 1% by weight in the photocurable pressure-sensitive adhesive composition. Within this range, curing by weak ultraviolet rays is blocked, thereby enhancing the storage stability of the photocurable material.

The heat stabilizer prevents oxidation of the pressure-sensitive adhesive composition and improves thermal stability. The heat stabilizer may include, but is not limited to, at least one member selected from the group consisting of a phenol compound, a quinone compound, an amine compound, and a phosphite compound. For example, the heat stabilizer may include tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, tris (2,4- . The heat stabilizer may be contained in an amount of 0.1 to 1% by weight in the photocurable pressure-sensitive adhesive composition. Within this range, deterioration of the material by heat can be prevented and the storage stability of the material can be enhanced.

The photocurable pressure-sensitive adhesive composition may further include a silane coupling agent for enhancing adhesion with 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. For example, a polymerizable fluorinated group-containing silicon compound such as 3-methacryloxypropyltrimethoxysilane, trimethoxysilane, or vinyltriethoxysilane; 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 1 to 5% by weight, preferably 1 to 3% by weight of the pressure-sensitive adhesive composition. Within the above range, adhesion with the glass base material is improved, and even after a predetermined time, the adhesive force of the material is further increased to maintain high adhesion force after commercialization.

The photocurable pressure-sensitive adhesive composition may further include a C1-20 alkyl (meth) acrylate, an aromatic (meth) acrylate, an epoxy acrylate, a polyester acrylate, and an acryl acrylate oligomer. The monomer and oligomer should have good compatibility with butadiene rubber binder, and can control viscosity and improve adhesion. The monomer and oligomer may have a number average molecular weight of 100 to 5000 g / mol, and may be included in the photocurable adhesive composition in an amount of 0 to 20% by weight. Within this range, the viscosity of the photocurable composition can be easily controlled and the adhesion with the glass can be increased. Also, it is effective to reduce shrinkage after photo-curing.

Examples of the C1-20 alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl Acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and dodecyl (meth) acrylate. These may be used alone or in combination of two or more. Here, (meth) acrylate means both acrylate and methacrylate.

Examples of the aromatic (meth) acrylate include 2-ethylphenoxy (meth) acrylate, 2-ethylthiophenyl (meth) acrylate, phenyl (meth) acrylate, benzyl (Meth) acrylate, 2-methylphenyl ethyl (meth) acrylate, 2-methylphenyl ethyl (meth) acrylate, 2 (Meth) acrylate, 2- (4-methylphenyl) ethyl (meth) acrylate, 2- (Meth) acrylate, 2- (4-cyclohexylphenyl) ethyl (meth) acrylate, 2- Ethyl (meth) acrylate, 2- (4-chlorophenyl) ethyl (meth) acrylate, 2- )Ah And the like, relay agent, and 2- (4-benzylphenyl) ethyl (meth) acrylate, such as methacrylic acid, but are not necessarily limited thereto. These may be used alone or in combination of two or more. Dibenzyl methacrylate, and benzyl acrylate are particularly preferable.

The photocurable pressure-sensitive adhesive composition of the present invention may have a hardening shrinkage of 3% or less, preferably 0.1 to 2.5%. The curing shrinkage ratio can be calculated as " [(specific gravity of the liquid composition before curing-solid specific gravity after curing)] / specific gravity of the liquid composition before curing x 100 &

Also, the photocurable pressure-sensitive adhesive composition of the present invention has a pH value of 4 or more, for example, 4 to 8, preferably 4.5 to 7. As the pH is above 4, the corrosion of the substrate can be minimized.

In another embodiment, the photocurable pressure-sensitive adhesive composition is characterized by having an elongation according to ASTM D412 of 200 to 800%.

The photocurable pressure-sensitive adhesive composition may have a modulus of 10 kPa to 50 kPa, preferably 15 kPa to 35 kPa. In the present invention, the modulus was measured by irradiating the pressure sensitive adhesive composition with a light quantity of 2000 mJ / cm < 2 > and curing the film to a thickness of about 500 mu m and a diameter of 25 mm. Then, ARES- At a rate of 25 ° C to 100 ° C (10 ° C / min).

The photocurable pressure-sensitive adhesive composition of the present invention can be preferably applied to a liquid pressure-sensitive adhesive used for an optical film or a substrate of a display device. Especially, it is useful for adhesion between cover window and ITO substrate.

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.

Example

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

(A) urethane (meth) acrylate resin: a binder having a weight average molecular weight of 20,000 g / mol, a polydispersity of 1.8, a Tg of -60 캜 and a viscosity (25 캜) of 43,000 cps ) Was used.

(B) Hydroxy group-containing polybutadiene: Poly bd 45HT having a weight average molecular weight of 7,000 g / mol, a polydispersity of 2.5, a hydroxyl value of 47, and a Tg of -75 was used, which was produced by Idemitsu Kosan Co., Ltd.

(C) Acrylic acid: LG Chem, purity more than 99%, water less than 0.3%

(D) 20 wt% of a photocurable monomer: 2-hydroxyethyl acrylate (LG Chem), 10 wt% of 3-methacryloxypropyltrimethoxysilane (KBM-503, Shin-Etsu Silicon) (Osaka Organic Chemical Co., Ltd.), 60 wt%, and acrylic mopolin (COGINE), 10 wt% were mixed and used.

(E) Photoinitiator: (1-Hydroxy-cyclohexyl-phenyl-ketone (IC-184, BASF) was used.

(F) Ultraviolet absorber: 3- (2H-Benzotriazolyl) -5- (1,1-di-methylethyl) -4-hydroxy-benzenepropanoic acid octyl esters, (Tinuvin 384 (BASF)) was used.

(G) Heat stabilizer: tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane (Antioxidant 1010 (BASF)) was used.

Example  1-6 and Comparative Example  1 to 6

Were added in the amounts shown in Table 1 below under an ultraviolet blocking lamp, and stirred at 400 rpm and 25 DEG C for 90 minutes. After stirring, the mixture was filtered through a 200-mesh filter and left at 25 DEG C for 48 hours. After allowing to stand for 2 days, the bubbles were completely removed, and the polyethylene terephthalate film as the coating release film was coated with 200 μm and 400 μm, respectively, and cured by applying energy of 2000 mJ / cm ² . After curing, optical properties such as light transmittance were evaluated for a 200 μm film, and mechanical properties such as elongation were evaluated for a 400 μm film.

Example Comparative Example Raw material name One 2 3 4 5 6 One 2 3 4 5 6 (A) 40 49 60 50 65 75 40 95 - - 40 40 (B) 17 21 20 5 5 5 - - 40 95 17 17 (C) - - - - - - - - - - One 5 (D) 38 25 15 40 25 15 55 - 55 - 37 33 (E) 4 4 4 4 4 4 4 4 4 4 4 4 (F) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (G) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

(Unit: wt%)

The physical properties of the optical pressure-sensitive adhesive films prepared in the Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Tables 2 and 3, respectively.

≪ Method for measuring physical properties &

1. Cure shrinkage ratio: The specific gravity of the liquid composition, the specific gravity of the solid after solidification, and the specific gravity of the liquid before light curing were measured with digital solid viscometer DME-220E (Shinko, Japan) The curing shrinkage ratio can be calculated as " [(specific gravity of the liquid composition before curing-solid specific gravity after curing)] / specific gravity of the liquid composition before curing x 100 &

2. Adhesive force: The adhesive force was measured by the same method as that for measuring the die shear strength as a method for measuring the adhesion between glass and glass. The adhesive strength meter dage series 4000PXY was used to measure the force exerted by pushing the upper glass from the side with a force of 200 kgf at 25 캜. The size of the lower glass was 2 cm x 2 cm x 1 mm, the size of the upper glass was 1.5 cm x 1.5 cm x 1 mm, and the thickness of the adhesive layer was 500 m.

3. Tensile Strength and Elongation: Specimen preparation and evaluation were conducted according to ASTM D412. The pressure-sensitive adhesive composition was coated on a polyethylene terephthalate film having a thickness of 500 탆 and cured at 6000 mJ / cm 2. The elongation was measured at a distance until the specimen was broken using Instron series IX / s Automated materials Tester-3343 Were measured at the same time.

4. Refractive index: Measured by the ASTM D1218 method. The composition was coated on a polyethylene terephthalate film having a thickness of 500 탆 and cured at 6000 mJ / cm 2, and the refractive index of the film was measured with an ABBE 5 (Bellingham / Stanley Ltd) instrument.

5. Visible light transmittance: The visible light transmittance of the prepared film was measured in a 550 nm region using a Lambda 950 (Perkin Elmer) instrument.

6. After curing Appearance: The photo-cured film was placed on paper with a white background, and stickiness and appearance abnormality were visually confirmed.

7. Modulus: The adhesive composition was irradiated with a light quantity of 2000 mJ / cm 2 and cured to a thickness of about 500 urn and a diameter of 25 mm. The film was then formed into ARES-G2 (TA Instruments) Deg.] C to 100 [deg.] C (10 [deg.] C / min).

8. Spreadability: 1 g of sample was dropped on a 10 cm × 10 cm 1 mm glass plate at a temperature of about 25 ° C., and the degree of spreading was measured by changing the area.

9. pH: 10 g of the sample was dissolved in 100 g of methyl ethyl ketone organic solvent and the pH value was measured with a pH meter (Mettler toledo inlab Routine Pro).

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Cure shrinkage (%) 2.17 1.93 1.84 2.34 2.10 1.86 Adhesion (kgf) 28 36 43 33 37 41 Tensile strength (gf / mm2) 18 21 25 22 33 37 Elongation (%) 250 320 350 270 260 230 Refractive index 1.48 1.48 1.48 1.48 1.48 1.48 Visible light transmittance (%) 99.2 99.3 99.1 99.2 99.2 99.1 Appearance after hardening Good Good Good Good Good Good Modulus (pa) 20400 22000 24800 19200 23200 28800 Liquid spreadability Good Good Good Good Good Good pH 4.8 5.2 5.3 4.6 5.2 5.3

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Cure shrinkage (%) 3.87 1.75 3.11 - 2.17 2.23 Adhesion (kgf) 25 53 18 - 34 58 Tensile strength (gf / mm2) 16 70 8 - 23 43 Elongation (%) 210 170 160 - 250 220 Refractive index 1.47 1.47 1.48 - 1.48 1.48 Visible light transmittance (%) 99.1 99.3 99.1 - 99.2 99.2 Appearance after hardening Good Good Buried on the surface Buried on the surface Good Good Modulus (pa) 12800 52000 6000 8800 20130 38300 Liquid spreadability Good Bad Good Bad Good Good pH 4.3 5.7 4.3 5.7 3.7 3.2

As shown in Tables 2 and 3, when the hydroxyl group-containing polybutadiene was not applied, the impact strength was deteriorated. In addition, when the urethane (meth) acrylate resin was not applied, the film formation ability after photopolymerization was lowered, resulting in a phenomenon of sticking to the surface. In contrast, the pressure-sensitive adhesive composition of the present invention has low shrinkage, high outdoor visibility, good adhesion, tensile strength, elongation, appearance and modulus balance, and a pH of 4 or more.

Claims (18)

A photo-curable pressure-sensitive adhesive composition comprising a urethane (meth) acrylate resin, a hydroxyl group-containing polybutadiene, a photo-curable monomer and a photoinitiator.
A urethane (meth) acrylate resin and a hydroxyl group-containing polybutadiene, and having a pH of 4 or more.
(Meth) acrylate resin and a hydroxyl group-containing polybutadiene having a curing shrinkage of 3% or less and an elongation of 200 to 800% according to ASTM D638.
The photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3, which comprises 35 to 75% by weight of a urethane (meth) acrylate resin, 5 to 30% by weight of a hydroxyl group-containing polybutadiene, 15 to 40 By weight of a photoinitiator and 1 to 5% by weight of a photoinitiator.
The photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the weight ratio between the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene is 70:30 to 95: 5.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the urethane (meth) acrylate resin and the hydroxyl group-containing polybutadiene are contained in an amount of 50 to 80% by weight of the total pressure-sensitive adhesive composition.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the urethane (meth) acrylate resin has a vinyl group at the terminal.
5. The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the urethane (meth) acrylate resin has a weight average molecular weight of 15,000 to 20,000 g / mol and a polydispersity of 1 to 3.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the urethane (meth) acrylate resin has a glass transition temperature of -65 to -55 占 폚 and a viscosity at 25 占 폚 of 25,000 to 35,000 cps.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the hydroxyl group-containing polybutadiene has a weight average molecular weight of 1,500 to 3,000 g / mol and a polydispersity of 1.2 to 2.2.
5. The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the hydroxyl group-containing polybutadiene has a hydroxy value of 1.7 to 1.9 meq / g and a butadiene group content of 70% or more.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the hydroxyl group-containing polybutadiene has a glass transition temperature of -80 to -70 ° C.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the hydroxyl group-containing polybutadiene has a vinyl group at the terminal.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the hydroxyl group-containing polybutadiene has a structure represented by the following formula (1):

[Chemical Formula 1]

(Where x is 0.1 to 0.35, y is 0.1 to 0.35, and z is 0.4 to 0.7).
The photocurable monomer according to claim 4, wherein the photocurable monomer is at least one member selected from the group consisting of (meth) acrylates having a hydroxy group, (meth) acrylates having an alicyclic ring of a monocyclic or heterocyclic ring, alicyclic heteroatoms having a nitrogen, (Meth) acrylic monomer having a ring, a (meth) acrylic monomer having a carboxyl group, and a monomer having a vinyl group and a silane group.
The photocurable pressure-sensitive adhesive composition according to claim 4, wherein the photocurable pressure-sensitive adhesive composition further comprises at least one additive selected from the group consisting of a silane coupling agent, an ultraviolet absorber, and a heat stabilizer.
The photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the modulus is 10 kPa to 50 kPa.
A display device comprising the photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3.