KR20110112068A - Optical film comprising acryl-based resin, and liquid-crystal-display comprising the same - Google Patents

Abstract

The present invention is an acrylic copolymer resin polymerized by including at least one of an alkyl (meth) acrylate monomer, a (meth) acrylate monomer including an aliphatic ring and / or an aromatic ring, and an imide monomer and a styrene monomer. ; And a resin including an aromatic ring and / or an aliphatic ring in the main chain; And a liquid crystal display device including the same. The optical film and the liquid crystal display device according to the present invention are excellent in heat resistance, optical transparency, and the like.

Description

Optical film containing an acrylic copolymer resin and a liquid crystal display including the same {OPTICAL FILM COMPRISING ACRYL-BASED RESIN, AND LIQUID-CRYSTAL-DISPLAY COMPRISING THE SAME}

The present invention relates to an optical film having excellent heat resistance and optical transparency including an acrylic copolymer resin having excellent heat resistance, and a liquid crystal display device including the optical film.

Recently, display technologies using various methods such as plasma display panels (PDPs) and liquid crystal displays (LCDs), which replace conventional CRTs, have been proposed and marketed based on the development of optical technologies. Polymer materials for such displays are becoming more sophisticated. For example, in the case of liquid crystal displays, as thin film thickness, light weight, and large screen area are promoted, wide viewing angles, high contrast, suppression of image color tone change according to viewing angle, and uniformity of screen display have become particularly important problems.

Accordingly, various polymer films are used for polarizing films, polarizer protective films, retardation films, plastic substrates, light guide plates, and the like. Twisted nematic (TN), super twisted nematic (STN) Various modes of liquid crystal displays using vertical alignment (VA), in-plane switching (IPS) liquid crystal cells, and the like have been developed. All of these liquid crystal cells have an inherent liquid crystal array, have inherent optical anisotropy, and in order to compensate for this optical anisotropy, films have been proposed in which various kinds of polymers are drawn to give a retardation function.

Specifically, since the liquid crystal display uses high birefringence characteristics and orientations of the liquid crystal molecules, the refractive index varies according to the viewing angle, and thus the color and brightness of the screen change. For example, since most liquid crystal molecules used in the vertical alignment method have a positive phase difference in the thickness direction of the liquid crystal display surface, a compensation film having a negative phase difference in the thickness direction is required to compensate for this. In addition, the front of the two polarizers orthogonal to each other do not pass light, but when the angle is inclined, the optical axis of the two polarizers are not orthogonal to cause light leakage, and a compensation film having a plane retardation is required to compensate for this. In addition, the display device using the liquid crystal requires both phase difference compensation in the thickness direction and plane direction difference compensation in order to widen the viewing angle.

A requirement for retardation compensation films is that birefringence must be easily controlled. By the way, the birefringence of the film is made not only by the fundamental birefringence of the material but also by the orientation of the polymer chain in the film. Orientation of the polymer chain is mostly caused by the force applied from the outside or due to the inherent properties of the material, the method of aligning the molecule by the external force is to stretch the polymer film uniaxially or biaxially.

In order to solve the viewing angle problem of LCDs due to the inherent birefringence characteristics of the liquid crystals, N-TAC, V-TAC, and COP films have recently been used as compensation films or retardation films. However, these films have a problem of high cost and complicated manufacturing process.

An object of the present invention, to solve the problems of the prior art as described above is to provide an optical film excellent in heat resistance and optical transparency, and a liquid crystal display device comprising the optical film.

The first aspect of the present invention for achieving the above object provides an optical film comprising the resin composition.

A second aspect of the present invention for achieving the above object provides a liquid crystal display device comprising the optical film.

The optical film and the liquid crystal display device according to the present invention are excellent in transparency and heat resistance, and excellent in workability, adhesiveness, retardation characteristics and durability.

1 to 4 illustrate an example in which the optical film according to the present invention is applied to a liquid crystal display device.

Hereinafter, the present invention will be described in detail.

The first aspect of the present invention is a combination of 1) alkyl (meth) acrylate monomers, 2) (meth) acrylate monomers including aliphatic rings and / or aromatic rings, and 3) imide monomers and styrene monomers. Acrylic copolymer resin polymerized including at least one; And

It relates to an optical film comprising a resin containing an aromatic ring and / or an aliphatic ring in the main chain.

In the present specification, the copolymer resin containing a monomer means that the monomer is polymerized and included as a repeating unit in the copolymer resin.

The acrylic copolymer may be a block copolymer or a random copolymer, but the copolymer form is not limited thereto.

The acrylic copolymer is an alkyl (meth) acrylate monomer; (Meth) acrylate monomers including aliphatic rings and / or aromatic rings; And it may be in the form of a ternary copolymer comprising a styrene-based monomer, it may be in the form of a quaternary copolymer further comprising an imide-based monomer, alkyl (meth) acrylate-based monomers; (Meth) acrylate monomers including aliphatic rings and / or aromatic rings; And ternary copolymer forms containing imide monomers.

In the acrylic copolymer resin, the alkyl (meth) acrylate monomer is 30 wt% or more and 90 wt% or less, and the (meth) acrylate monomer containing an aliphatic ring and / or an aromatic ring is more than 0 wt% 50 It is preferable that it is weight% or less. In addition, the imide monomer is preferably 0.1 wt% or more and 50 wt% or less, and the styrene monomer is preferably 0.1 wt% or more and 50 wt% or less, and these may be included in the acrylic copolymer simultaneously or alone.

In the acrylic copolymer resin, an alkyl (meth) acrylate monomer means both an alkyl acrylate monomer and an alkyl methacrylate monomer. It is preferable that the alkyl group of the said alkyl (meth) acrylate type monomer is C1-C10, It is more preferable that it is 1-4, It is more preferable that it is a methyl group or an ethyl group. The alkyl methacrylate monomer is more preferably methyl methacrylate, but is not limited thereto.

The content of the alkyl methacrylate monomer in the acrylic copolymer resin is preferably 30 to 90% by weight, more preferably 50 to 90% by weight. When the content of the alkyl methacrylate monomer is within the above range, excellent transparency may be maintained while heat resistance.

The (meth) acrylate monomer containing an aliphatic ring and / or an aromatic ring in the acrylic copolymer resin serves to improve the heat resistance of the acrylic copolymer resin according to the present invention, for example, cycloalkyl (meth) acrylic It may be a rate monomer or an aryl (meth) acrylate monomer.

The cycloalkyl group of the cycloalkyl (meth) acrylate monomer is preferably 4 to 12 carbon atoms, more preferably 5 to 8 carbon atoms, and most preferably a cyclohexyl group. In addition, the aryl group of the aryl (meth) acrylate monomer is preferably 6 to 12 carbon atoms, most preferably a phenyl group.

Specific examples of the (meth) acrylate monomers containing the aliphatic ring and / or the aromatic ring include cyclopentyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, cyclohexyl acrylate and 2-phenoxyethyl acryl. Latex, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, 3-cyclohexylpropyl methacrylate, phenyl methacrylate, 4-t-butylphenyl methacrylate, 4-methoxy phenyl methacrylate, 1-phenylethyl methacrylate, 2-phenylethyl acrylate, 2- phenylethyl methacrylate, 2-phenoxyethyl methacrylate, 2-naphthyl methacrylate, etc. And cyclohexyl methacrylate or phenyl methacrylate are preferred, but not limited thereto.

In the acrylic copolymer resin, the content of the (meth) acrylate monomer including the aliphatic ring and / or the aromatic ring is preferably more than 0% by weight and 50% by weight or less, and more than 0% by weight and 30% by weight or less. It is preferable that it is 5 weight% or more and 30 weight% or less. When the content of the (meth) acrylate-based monomer including an aliphatic ring and / or an aromatic ring is in the above range, heat resistance can be sufficiently secured.

In the acrylic polymer, the imide monomer means a monomer including an imide group, and examples thereof include maleimide. Among these, maleimide substituted with a cycloalkyl group or an aryl group is preferable for improving the heat resistance of the acrylic copolymer.

The cycloalkyl group which may be substituted in the imide monomer is preferably a cycloalkyl group having 3 to 15 carbon atoms, and more preferably a cyclohexyl group. In addition, the aryl group which may be substituted in the imide monomer is preferably 6 to 15 carbon atoms, more preferably a phenyl group.

Specific examples of the imide monomers include N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-naphthylmaleimide, N-hydroxyphenylmaleimide, N -Methoxyphenyl maleimide, N-carboxyphenyl maleimide, N-nitrophenyl maleimide, N-tribromophenyl maleimide, etc. are mentioned. These monomers may be used independently and may use 2 or more types together. Of these monomers, N-cyclohexylmaleimide or N-phenylmaleimide is particularly preferred, but is not limited thereto.

In the acrylic copolymer resin, the content of the imide monomer is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight. When the content of the imide-based monomer is in the above range, it is preferable because the decrease in mechanical strength can be minimized while ensuring heat resistance.

In the acrylic copolymer, the styrene monomer refers to a monomer including a styrene group, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5- Dimethylstyrene, 2-methyl-4-chlorostyrene, 2,4,6-trimethylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluor-α- Methylstyrene, 4-chloro-α-methylstyrene, 4-bromo-α-methylstyrene, 4-t-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-di Fluorostyrene, 2,3,4,5,6-pentafluorostyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, Octachlorostyrene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene, 4 -Hydroxy tea And the like. Of these monomers, α-methylstyrene is most preferred in view of ease of copolymerization and heat resistance, but is not limited thereto.

In the acrylic copolymer resin, the content of the styrene monomer is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight. When the content of the styrene-based monomer is in the above range, it is preferable because the decrease in mechanical strength can be minimized while ensuring heat resistance.

In addition, the molecular weight of the acrylic copolymer resin is preferably in the range of 50,000 to 500,000 in terms of heat resistance, processability and productivity.

Glass transition temperature (Tg) of the said acrylic copolymer resin becomes like this. Preferably it is 120 degreeC or more, More preferably, it is 130 degreeC or more. The glass transition temperature of the acrylic copolymer resin is not particularly limited, but may be 200 ° C. or less.

As the resin containing an aromatic ring and / or an aliphatic ring in the main chain, for example, polycarbonate resin, polyarylate resin, polynaphthalene resin, polynorbornene resin, or the like can be used. More preferably, it is not limited to this.

It is preferable that the weight ratio of the said acrylic copolymer resin and resin containing an aromatic ring and / or an aliphatic ring in the said main chain is 60-99.9: 0.1-40, and it is more preferable that it is 70-99: 1-30.

The acrylic copolymer resin and the resin containing an aromatic ring and / or an aliphatic ring in the main chain may be prepared by blending according to a method well known in the art, such as compounding method, colorants, flame retardants, reinforcing agents, fillers, UV stabilizers It may include 0.001 to 70 parts by weight of additives well known in the art, such as antioxidants.

It is preferable that it is 110 degreeC or more, and, as for the glass transition temperature of the blending resin of the said acrylic copolymer resin and resin which contains an aromatic ring and / or an aliphatic ring in the said main chain, it is more preferable that it is 120 degreeC or more. The glass transition temperature is not particularly limited, but may be 200 ° C. or less.

The weight average molecular weight of the blended resin of the acrylic copolymer resin and the resin containing an aromatic ring and / or an aliphatic ring in the main chain is preferably 50,000 to 500,000 in terms of heat resistance, sufficient processability, productivity, and the like.

The optical film according to the present invention may have different retardation values depending on the content of the resin containing an aromatic ring and / or an aliphatic ring in the main chain, and thus may be used as a retardation compensation film or a protective film.

The retardation compensation film may be used in the VA mode type or the TN mode type according to the retardation value. The optical film according to the present invention may have a plane direction retardation value (R _in ) of 30 nm to 80 nm and a thickness direction retardation value (R _th ) of -50 nm to -300 nm, in which case it may be used as a VA mode type retardation compensation film. In addition, the optical film according to the present invention may have a plane direction retardation value (R _in ) of 150 nm to 200 nm and a thickness direction retardation value (R _th ) of -90 nm or less, that is, an absolute value of 90 or more of the thickness direction retardation value, in this case, It can be used as a TN mode retardation compensation film. When used as the TN mode retardation compensation film, the thickness direction retardation value (R _th ) is more preferably -90nm to -150nm.

As one example, when the content of the resin containing an aromatic ring and / or aliphatic ring in the main chain is 10% to 40% by weight, the plane direction retardation value (R _in ) of the optical film may be 30nm to 80nm The thickness direction retardation value R _th may be -50 nm to -300 nm. In this case, the optical film according to the present invention can be used as a VA mode type retardation compensation film.

As another example, when the content of the resin containing an aromatic ring and / or an aliphatic ring in the main chain is 0.1% to 10% by weight, more preferably 1% to 5% by weight, the plane direction retardation of the optical film The value R _in may be 0 nm to 10 nm, preferably 0 nm to 5 nm, more preferably about 0 nm, and the thickness direction retardation value R _th may be -10 nm to 10 nm, preferably -5 nm to 5 nm. And more preferably about 0 nm. In this case, the optical film according to the present invention can be used as a polarizer protective film.

The optical film may be prepared into a film according to a method well known in the art such as a solution caster method or an extrusion method, of which a solution caster method is preferable.

It may further comprise the step of uniaxially or biaxially stretching the film prepared as described above, may be prepared by adding a modifier in some cases.

When the film is uniaxially or biaxially stretched, the stretching step may be performed in the longitudinal direction (MD) stretching or in the transverse direction (TD) stretching, or both. When extending | stretching both a longitudinal direction and a lateral direction, after extending | stretching either one, you can extend in another direction and you may extend | stretch both directions simultaneously. Stretching can be done in one step or stretched in multiple steps. When extending | stretching in a longitudinal direction, extending | stretching by the speed difference between rolls can be performed, and when extending | stretching in a lateral direction, a tenter can be used. The starting angle of the tenter is 10 degrees or less in total, suppressing the bowing phenomenon which arises at the time of a lateral stretch, and controls the angle of an optical axis regularly. The same boeing suppression effect can also be obtained by making transverse stretching into multiple stages.

The stretching may be performed at a temperature of (Tg-20 ° C) to (Tg + 30 ° C) when the glass transition temperature of the resin composition is Tg. The glass transition temperature refers to a region from the temperature at which the storage modulus of the resin composition begins to decrease, and thus the loss modulus becomes larger than the storage modulus, at which the orientation of the polymer chain is relaxed and lost. Glass transition temperatures can be measured by differential scanning calorimetry (DSC). The temperature at the time of the stretching step is more preferably the glass transition temperature of the film.

The drawing speed is preferably in the range of 1 to 100 mm / min in the case of a universal drawing machine (Zwick Z010) and in the range of 0.1 to 2 m / min in the case of a pilot drawing machine. It is preferable to stretch the film by applying an elongation of 5 to 300%.

The optical film according to the present invention can be uniaxially or biaxially stretched by the above-described method, thereby adjusting the phase difference characteristics.

In the optical film manufactured as described above, the plane direction retardation value represented by Equation 1 below is preferably 0 nm to 200 nm, and the thickness direction retardation value represented by Equation 2 below is preferably 10 nm to -300 nm.

[Equation 1]

R _in = (n _x -n _y ) × d

[Equation 2]

R _th = (n _z -n _y ) × d

In Equations 1 and 2,

n _x is a refractive index of the direction of the largest refractive index in the plane direction of the film,

n _y is a refractive index in the vertical direction in the n _x direction in the plane direction of the film,

n _z is the refractive index in the thickness direction,

d is the thickness of the film.

In the optical film according to the present invention, the surface direction retardation value and the thickness direction retardation value may be adjusted according to the content of the resin including the aromatic ring and / or the aliphatic ring in the main chain. For example, the planar retardation value R _in of the optical film according to the present invention may be 20 nm to 80 nm, and the thickness direction retardation value R _th may be -50 nm to -300 nm. In this case, the optical film according to the present invention can be used as a VA mode type retardation compensation film. In addition, the plane direction retardation value R _in of the optical film according to the present invention may be 0 nm to 10 nm, preferably 0 nm to 5 nm, more preferably about 0 nm, and the thickness direction retardation value R _th is −10 nm. It may be from 10nm, preferably -5nm to 5nm, more preferably about 0nm. In this case, the optical film according to the present invention can be used as a polarizer protective film.

When the optical film according to the present invention is provided only on one side of the liquid crystal panel, the plane direction retardation value R _in of the optical film is 30 nm to 80 nm, preferably 35 nm to 70 nm, and more preferably about 40 nm to 60 nm. The thickness direction retardation value R _in is preferably -270 nm or less, that is, the thickness direction retardation value is preferably 270 or more in absolute value.

When the optical film according to the present invention is provided on both sides of the liquid crystal panel, respectively, the plane retardation value R _in of the optical film is 30 nm to 80 nm, preferably 35 nm to 70 nm, and more preferably about 40 nm to 60 nm. It is preferable that the thickness direction retardation value R _in is -100 nm or less, that is, the thickness direction retardation value is preferably 100 or more in absolute value.

The optical film according to the present invention is characterized in that the photoelastic coefficient is smaller than that of the conventional TAC film. The photoelastic coefficient of the optical film according to the present invention may be 10 or less, preferably 8 or less, more preferably 0.1 or more and 7 or less, and more preferably 0.5 or more and 6 or less.

The brittleness of the optical film according to the present invention can be measured by dropping a steel sphere having a particle diameter of 15.9 mm and a weight of 16.3 g on a test film to measure a height at which a hole is formed in the film, and the optical film according to the present invention has the height Preferably it is 600 mm or more, More preferably, it is 700 nm or more.

It is preferable that the haze value of the optical film which concerns on this invention is 1% or less, It is more preferable that it is 0.5% or less, It is further more preferable that it is 0.1% or less.

A second aspect of the present invention relates to a liquid crystal display device including the optical film.

An example in which the optical film according to the present invention is used as a protective film is shown in FIG. 2. In FIG. 2, both of the protective films provided on both surfaces of the two polarizing plates are optical films according to the present invention, and at least one of the protective films may be a conventional protective film.

When the optical film according to the present invention is applied to the liquid crystal display device, it may be provided on only one side of the liquid crystal panel (one sheet type), or may be provided on both sides of the liquid crystal panel (two sheets type). Although one sheet type is illustrated in FIG. 3 and two sheet types are illustrated in FIG. 4, the scope of the present invention is not limited thereto.

The liquid crystal display device is preferably a VA (vertical alignment) mode type or a TN mode type liquid crystal display device. Hereinafter, the VA mode type will be mainly described. However, the optical film according to the present invention may be applied to a TN mode type liquid crystal display device.

In the VA mode liquid crystal display, an optical film can be used for viewing angle compensation, which has two elements to be compensated for. The first is compensation for light leakage of the polarizing plate when the absorption axis of the two polarizing plates is not orthogonal in appearance when the liquid crystal display is tilted, and the second is birefringence of the liquid crystal molecules when the VA cell is observed from the inclined direction. This is necessary compensation because light leakage due to cell generation occurs during black display, whereby a decrease in contrast is observed.

Since the polarizer combined with the optical film is made of a uniaxially stretched polyvinyl alcohol film containing a dichroic dye, the polarizer is very fragile and is laminated with a protective film because its durability against temperature and moisture is poor. If the optical film can be directly adhered to the polarizer instead of the protective film, a thinned retardation film integrated polarizing film for one layer of the protective film can be obtained.

Since the cellulose derivative has excellent water permeability, the cellulose derivative has an advantage in that the water contained in the polarizer can be volatilized through the film in the manufacturing process of the polarizing plate. However, on the other hand, in the high temperature and high humidity atmosphere, the dimensional change and optical property change due to moisture absorption are relatively large, and the phase difference value when the humidity is changed near room temperature is large, so that there is a limit in improving the stable viewing angle. There is a problem that the durability is lowered.

In addition, in the polycarbonate system, the glass transition temperature is high, so that not only the stretching at high temperature is required but also the photoelastic coefficient of the film is large, thereby causing optical deformation due to stress. When extending | stretching a norbornene-type film, there exists a problem of the stress at the time of extending | stretching or the stress nonuniformity at the time of extending | stretching generate | occur | producing. The solution of this problem can be solved by adopting an acryl-based retardation film having a good viewing angle compensation effect and a small change in retardation value even with environmental changes.

The liquid crystal display including one or two or more optical films according to the present invention will be described in more detail as follows.

A liquid crystal display device comprising a liquid crystal cell and a first polarizing plate film and a second polarizing plate film respectively provided on both surfaces of the liquid crystal cell, wherein the optical film is between the liquid crystal cell and the first polarizing plate film and / or the second polarizing plate film. It may be provided in. That is, an optical film may be provided between the first polarizing plate film and the liquid crystal cell, and may be provided between the second polarizing plate film and the liquid crystal cell, or between the first polarizing plate film and the liquid crystal cell and between the second polarizing plate film and the liquid crystal cell. One or two films It may be provided.

The first polarizing plate film and the second polarizing plate film may include a protective film on one or both surfaces. The inner protective film may include a triacetate cellulose (TAC) film, a polynorbornene-based film made of ring opening metathesis polymerization (ROMP), and a hydrogenated cyclic olefin-based polymer that is ring-opened polymerized. ring opening metathesis polymerization followed by hydrogenation) may be a polymer film, a polyester film, or a polynorbornene-based film made by addition polymerization. In addition, a film made of a transparent polymer material may be used as a protective film, but is not limited thereto.

In addition, the present invention provides an integrated polarizing plate including a polarizing film and including the optical film according to the present invention on one or both surfaces of the polarizing film as a protective film.

When only one surface of the polarizing film is provided with the optical film according to the present invention, the other surface may be provided with a protective film known in the art.

As the polarizing film, a film made of polyvinyl alcohol (PVA) containing iodine or dichroic dye may be used. The polarizing film may be prepared by dyeing iodine or dichroic dye on a PVA film, but a method of manufacturing the same is not particularly limited. In the present specification, the polarizing film means a state not including a protective film, and the polarizing plate means a state including a polarizing film and a protective film.

In the integrated polarizing plate of the present invention, the protective film and the polarizing film may be laminated by a method known in the art.

For example, the lamination of the protective film and the polarizing film may be made by an adhesive method using an adhesive. That is, first, an adhesive is coated on the surface of the PVA film, which is a protective film of the polarizing film or a polarizing film, using a roll coater, a gravure coater, a bar coater, a knife coater or a capillary coater. Before the adhesive is completely dried, the protective film and the polarizing film are laminated by heat pressing at room temperature or pressing at room temperature. In the case of using a hot melt adhesive, a heat press roll should be used.

Adhesives that can be used when the protective film and the polarizing plate are laminated include one-component or two-component PVA adhesives, polyurethane adhesives, epoxy adhesives, styrene butadiene rubber (SBR) adhesives, or hot melt adhesives, but are not limited thereto. Do not. When using a polyurethane adhesive, it is preferable to use the polyurethane adhesive manufactured using the aliphatic isocyanate type compound which does not yellow by light. When using one-component or two-component dry laminate adhesives or adhesives with relatively low reactivity between isocyanates and hydroxyl groups, a solution-type adhesive diluted with an acetate solvent, a ketone solvent, an ether solvent, or an aromatic solvent may be used. Can also be used. At this time, the adhesive viscosity is preferably low viscosity of 5,000 cps or less. It is preferable that the adhesives have excellent storage stability and have a light transmittance of 90% or more at 400 to 800 nm.

A tackifier can also be used if it can exert sufficient adhesive force. It is preferable that the adhesive is sufficiently cured by heat or ultraviolet rays after lamination, and thus the mechanical strength is improved to the level of the adhesive. The adhesive strength is also large so that the adhesive does not peel off without breaking of either film to which the adhesive is attached. It is preferable.

Specific examples of the pressure-sensitive adhesive that can be used include natural rubber, synthetic rubber or elastomer having excellent optical transparency, a vinyl chloride / vinyl acetate copolymer, polyvinyl alkyl ether, polyacrylate or modified polyolefin-based pressure-sensitive adhesive, and a curing type in which a curing agent such as isocyanate is added thereto. An adhesive is mentioned.

In addition, the present invention provides a liquid crystal display device including the integrated polarizer. Although the structure of the liquid crystal display device according to the present invention is shown in FIG. 1, the scope of the present invention is not limited thereto.

Even when the liquid crystal display according to the present invention includes the above-mentioned integrated polarizing plate, one or more optical films according to the present invention may be further included between the polarizing plate and the liquid crystal cell.

Hereinafter, preferred examples will be described to aid in understanding the present invention. The following examples are merely to illustrate the invention, but are not intended to limit the scope of the invention.

The physical property evaluation method in this invention is as follows.

1. Weight average molecular weight (Mw): The prepared resin was dissolved in tetrahydrofuran and measured by gel osmosis chromatography (GPC).

2. Tg (glass transition temperature): Measured using a DSC (Differential Scanning Calorimeter) from TA Instrument.

3. Retardation value (Rin / Rth): After stretching at the glass transition temperature of the film was measured using AxoScan from Axometrics.

4. Haze value (transparency): The haze value was measured using HAZEMETER HM-150 of Murakami color Research Laboratory.

Example

≪ Example 1 >

The resin was prepared from 82 wt% methyl methacrylate, 10 wt% cyclohexyl methacrylate, 3 wt% alphamethyl styrene, and 5 wt% N-cyclohexyl maleimide. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin of glass transition temperature 135 degreeC and molecular weight 80,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the plane retardation value / thickness retardation value was 48 / -130, and the Haze value was 0.1.

<Example 2>

The resin was prepared from 65 wt% methyl methacrylate, 10 wt% cyclohexyl methacrylate, 10 wt% styrene, and 15 wt% N-cyclohexyl maleimide. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin with glass transition temperature of 130 degreeC and molecular weight 90,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the surface retardation value / thickness retardation value was 43 / -125, and the Haze value was 0.1.

<Example 3>

The resin was prepared from 65 wt% methyl methacrylate, 20 wt% cyclohexyl methacrylate, 5 wt% alphamethyl styrene, and 10 wt% phenyl maleimide. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin of glass transition temperature 131 degreeC and molecular weight 80,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the plane retardation value / thickness retardation value was 40 / -115, and the Haze value was 0.1.

<Example 4>

The resin was prepared from 82 wt% methyl methacrylate, 10 wt% benzyl methacrylate, 3 wt% alphamethyl styrene, and 5 wt% N-cyclohexyl maleimide. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin of glass transition temperature 130 degreeC and molecular weight 90,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the plane retardation value / thickness retardation value was 48 / -140, and the Haze value was 0.1.

Example 5

The resin was prepared from 80 wt% methyl methacrylate, 10 wt% cyclohexyl methacrylate, and 10 wt% alphamethyl styrene. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin with a glass transition temperature of 130 degreeC and a molecular weight of 75,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the plane retardation value / thickness retardation value was 55 / -95, and the Haze value was 0.1.

<Example 6>

The resin was prepared from 80 wt% methyl methacrylate, 15 wt% cyclohexyl methacrylate, and 5 wt% N-cyclohexyl maleimide. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin with a glass transition temperature of 118 degreeC and a molecular weight of 85,000 was obtained. The resin and the polycarbonate were mixed at a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the surface retardation value / thickness retardation value was 43 / -90, and the Haze value was 0.1.

Comparative Example 1

Resin was prepared from 80 wt% methyl methacrylate and 20 wt% cyclohexyl methacrylate. As a result of measuring the glass transition temperature and molecular weight of manufactured resin, the resin with a glass transition temperature of 119 degreeC and molecular weight 100,000 was obtained. The resin and the polycarbonate were mixed in a weight ratio of 90:10 and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. As a result, the plane retardation value / thickness retardation value was 35 / -100, and the Haze value was 0.1.

The above Examples and Comparative Examples are summarized in Table 1 and Table 2 below.

Monomer (% by weight) MMA CHMA BzMA Styrene series Imide Example 1 82 10 - AMS 3 CHMI 5 Example 2 65 10 - SM 10 CHMI 15 Example 3 65 20 - AMS 5 PMI 10 Example 4 82 - 10 AMS 3 CHMI 5 Example 5 80 10 - AMS 10 - Example 6 80 15 - - CHMI 5 Comparative Example 1 80 20 - - -

MMA: Methyl methacrylate

CHMA: cyclohexyl methacrylate BzMA: benzyl methacrylate

AMS: Alphamethyl Styrene

SM: Styrene

CHMI: N-cyclohexyl maleimide

PMI: Phenyl Maleimide

Haze (%) Tg (占 폚) Mw R _in (nm) R _th (nm) Example 1 0.1 135 80,000 48 -130 Example 2 0.1 130 90,000 43 -125 Example 3 0.1 131 80,000 40 -115 Example 4 0.1 130 90,000 48 -140 Example 5 0.1 130 75,000 55 -95 Example 6 0.1 118 85,000 43 -90 Comparative Example 1 0.1 119 100,000 35 -100

< Example  7 to 21

To prepare a copolymer resin with a monomer composition as shown in Table 3, it was mixed with polycarbonate and compounded to prepare a final resin composition. After producing this resin composition into the film by the solution casting method, extending | stretching was performed at the glass transition temperature and the phase difference value of the film was measured. Physical properties of the produced film are shown in Table 4 below.

Monomer (% by weight) Acrylate resin (part by weight) PC
(Parts by weight) Miscibility MMA Ring-containing (meth) acrylate monomers Styrene series Imide Example 7 80 CHMA 10 - PMI 10 90 10 O Example 8 60 CHMA 20 - CHMI 15 88 12 O Example 9 82 CHMA 10 AMS 3 PMI 5 88 12 O Example 10 60 CHMA 15 SM 10 CHMI 15 90 10 O Example 11 80 BzMA 10 - PMI 10 90 10 O Example 12 82 BzMA 10 AMS 3 CHMI 5 88 12 O Example 13 75 BzMA 15 SM 10 - 90 10 O Example 14 85 PhMA 10 - PMI 5 80 20 O Example 15 70 PhMA 20 - CHMI 10 75 25 O Example 16 75 PhMA 10 AMS 3 PMI 5 80 20 O Example 17 65 PhMA 15 SM 8 PMI 12 77 23 O Example 18 80 CHMA 10 - PMI 10 98 2 O Example 19 85 PhMA 10 - CHMI 5 98.5 1.5 O Example 20 82 CHMA 10 AMS 3 PMI 5 99 One O Example 21 75 PhMA 10 SM 5 CHMI 10 99.2 0.8 O Comparative Example 1 80 CHMA 20 - - 90 10 O

PhMA: Phenyl methacrylate

Tg Mw Rin Rth Photoelastic coefficient Example 7 130 80000 40 -111 3.8 Example 8 132 90000 50 -121 4.2 Example 9 135 80000 52 -125 4.1 Example 10 130 85000 42 -105 3.9 Example 11 128 85000 41 -100 4 Example 12 130 80000 51 -186 4.3 Example 13 128 80000 50 -99 4 Example 14 130 95000 56 -275 5.5 Example 15 131 100000 65 -296 6 Example 16 133 80000 60 -263 5.2 Example 17 130 90000 59 -273 5.7 Example 18 130 80000 1.3 -2.1 1.1 Example 19 129 95000 0.5 -1.5 0.9 Example 20 130 85000 1.5 -0.6 0.6 Example 21 133 90000 0.3 -0.7 0.5 Comparative Example 1 119 100000 45 -100 4

 The brittleness of the films prepared in Examples 12 to 14 was measured by dropping steel balls having a particle diameter of 15.9 mm and a weight of 16.3 g on the film to measure the height at which holes were formed in the film. The measured height is shown in Table 5 below.

Example 12 Example 13 Example 15 The height of the hole in the film 740 mm 700 mm 710 mm

Claims (20)

An acrylic copolymer resin polymerized including at least one of an (meth) acrylate monomer including an alkyl (meth) acrylate monomer, an aliphatic ring and / or an aromatic ring, and an imide monomer and a styrene monomer; And
An optical film comprising a resin containing an aromatic ring and / or an aliphatic ring in the main chain. The optical film of claim 1, wherein the (meth) acrylate monomer including the aliphatic ring and / or the aromatic ring is a cycloalkyl (meth) acrylate monomer or an aryl (meth) acrylate monomer. The optical film of claim 2, wherein the cycloalkyl group of the cycloalkyl (meth) acrylate monomer has 4 to 12 carbon atoms, and the aryl group of the aryl (meth) acrylate monomer has 6 to 12 carbon atoms. . The method of claim 1, wherein the (meth) acrylate monomer containing an aliphatic ring and / or an aromatic ring is cyclopentyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, cyclohexyl acrylate, 2-phenoxy Ethyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, 3-cyclohexylpropyl methacrylate, phenyl methacrylate, 4-t-butylphenyl methacrylate Latex, 4-methoxypentyl methacrylate, 1-phenylethyl methacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate, 2-phenoxyethyl methacrylate and 2-naphthyl methacrylate Optical film, characterized in that selected from the group consisting of. The optical film of claim 1, wherein the imide monomer is maleimide unsubstituted or substituted with a cycloalkyl group or an aryl group. The method of claim 1, wherein the imide monomer is N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-naphthylmaleimide, N-hydroxyphenylmaleimide , N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide and N-tribromophenylmaleimide. The method of claim 1, wherein the styrene monomer is styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2-methyl-4-chlorostyrene, 2,4,6-trimethylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluor-α-methylstyrene, 4-chloro-α-methylstyrene, 4-bromo-α-methylstyrene, 4-t-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2,3,4,5, 6-pentafluorostyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, octachlorostyrene, 2-bromostyrene, 3- Bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene Optical pen Name. The optical method of claim 1, wherein the resin including an aromatic ring and / or an aliphatic ring in the main chain is selected from the group consisting of polycarbonate resin, polyarylate resin, polynaphthalene resin, and polynorbornene resin. film. The optical film according to claim 1, wherein the weight ratio of the acrylic copolymer resin and the resin containing an aromatic ring and / or an aliphatic ring in the main chain is 60 to 99.9: 0.1 to 40. The optical film according to claim 1, wherein the optical film is used for a retardation compensation film or a protective film. The optical film as set forth in claim 1, wherein the optical film has a plane direction retardation value represented by Equation 1 below −5 nm to 200 nm.
[Equation 1]
R _in = (n _x -n _y ) × d
In Equation 1,
n _x is a refractive index of the direction of the largest refractive index in the plane direction of the film,
n _y is a refractive index in the vertical direction in the n _x direction in the plane direction of the film,
d is the thickness of the film. The optical film according to claim 1, wherein the optical film has a thickness direction retardation value of 5 nm to -300 nm represented by the following Equation 2.
[Equation 2]
R _th = (n _z -n _y ) × d
In Equation 2,
n _x is a refractive index of the direction of the largest refractive index in the plane direction of the film,
n _y is a refractive index in the vertical direction in the n _x direction in the plane direction of the film,
n _z is the refractive index in the thickness direction,
d is the thickness of the film. The optical film according to claim 1, wherein the optical film has a plane direction retardation value of 20 nm to 80 nm represented by Equation 1 below, and a thickness direction retardation value represented by Equation 2 below is -50 nm to -300 nm. :
[Equation 1]
R _in = (n _x -n _y ) × d
[Equation 2]
R _th = (n _z -n _y ) × d
In Equations 1 and 2,
n _x is a refractive index of the direction of the largest refractive index in the plane direction of the film,
n _y is a refractive index in the vertical direction in the n _x direction in the plane direction of the film,
n _z is the refractive index in the thickness direction,
d is the thickness of the film. The optical film according to claim 1, wherein the optical film has a plane direction retardation value represented by Equation 1 below 0 nm to 10 nm, and a thickness direction retardation value represented by Equation 2 below −10 nm to 10 nm.
[Equation 1]
R _in = (n _x -n _y ) × d
[Equation 2]
R _th = (n _z -n _y ) × d
In Equations 1 and 2,
n _x is a refractive index of the direction of the largest refractive index in the plane direction of the film,
n _y is a refractive index in the vertical direction in the n _x direction in the plane direction of the film,
n _z is the refractive index in the thickness direction,
d is the thickness of the film. The optical film of claim 1, wherein the optical film has a haze value of 1% or less. Claim 1 to 15 of any one of the optical film; Polarizer; And a liquid crystal cell essentially, and further comprising a protective film. A first polarizing plate film formed by sequentially stacking a protective film, a polarizer, and an optical film of any one of claims 1 to 15; A second polarizing plate film having a polarizer interposed and laminated between a pair of protective films; And a liquid crystal cell interposed and laminated between the first polarizing plate film and the second polarizing plate film. The 1st polarizing plate film and the 2nd polarizing plate film which a polarizer is interposed and laminated between one pair of optical films of any one of Claims 1-15; And a liquid crystal cell interposed and laminated between the first polarizing plate film and the second polarizing plate film. A first polarizing plate film and a second polarizing plate film, wherein a polarizer is interposed and laminated between a pair of protective films; And an optical film and a liquid crystal cell according to any one of claims 1 to 15 are interposed between the first polarizing film and the second polarizing film. A first polarizing plate film and a second polarizing plate film, wherein a polarizer is interposed and laminated between a pair of protective films; And a pair of optical films of any one of claims 1 to 15 and a liquid crystal cell interposed and stacked between the first polarizing plate film and the second polarizing plate film, wherein the liquid crystal cell is interposed between the pair of optical films. A liquid crystal display device which is laminated.

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