KR101315512B1 - (meth)acrylic resin composition and optical film comprising the same - Google Patents

Abstract

The present invention relates to a (meth) acrylic resin composition and an optical film comprising the same. The optical film according to the present invention is excellent in transparency, optical properties, ultraviolet absorbing effect and the like.

Description

(Meth) acrylic resin composition and optical film containing same {(METH) ACRYLIC RESIN COMPOSITION AND OPTICAL FILM COMPRISING THE SAME}

The present invention relates to a (meth) acrylic resin composition and an optical film comprising the same.

In the polarizing plate used for a liquid crystal display device etc., the protective film for PVA polarizers may require ultraviolet absorption performance in order to prevent a liquid crystal or a polarizer from ultraviolet-ray deterioration. At present, an ultraviolet absorber is added to a triacetyl cellulose film (hereinafter TAC) as a polarizer protective film to provide ultraviolet absorbing performance.

However, a TAC film does not have enough heat and moisture resistance, and when the polarizing plate using a TAC film as a polarizer protective film is used under high temperature or high humidity, there exists a fault that the performance of polarizing plates, such as polarization degree and a hue, falls. Therefore, as a material of the polarizer protective film which replaces the conventional TAC film, transparent acrylic resin is examined, and the polarizer protective film which adds an ultraviolet absorber to transparent acrylic resin and has ultraviolet absorption performance is also reported. In this case, the ultraviolet absorber used is a benzotriazole-based compound, a benzophenone-based compound, a cyano acrylate-based compound, or a salicylic acid-based compound added to the film to deteriorate due to ultraviolet rays. Is preventing.

However, most of the above-mentioned ultraviolet absorbers decompose during high temperature processing to reduce the amount of addition and lower the ultraviolet absorbing ability, and have a problem of coloring the resin and the film yellow. Therefore, the ultraviolet absorber should also be able to absorb ultraviolet light effectively while maintaining the transparency of the film even after being made into the film without decomposing at high temperature. In addition, the glass transition temperature (Tg) after addition compared to the glass transition temperature (Tg) of the material resin before the addition of the ultraviolet absorber is greatly reduced (a problem of lowering heat resistance) and when exposed to ultraviolet rays for a long time. There is also a problem that the ultraviolet absorption capacity is reduced or the optical properties of the optical film itself changes.

Accordingly, in the polarizer protective optical film, while solving the above problems, it is required to effectively block ultraviolet rays at 300 to 400nm and to sufficiently transmit the light in the visible light region of 400 nm or more.

Accordingly, the present invention is to provide a (meth) acrylic resin composition for manufacturing an optical film having excellent transparency, optical properties, and the like, and excellent ultraviolet absorption effect, and an optical film including the same.

This invention provides the (meth) acrylic-type resin composition for optical film manufacture whose color change value ((DELTA) a, (DELTA) b) of the film before and behind UV exposure satisfy | fills following formula (1) and (2), respectively.

In Equation 1, a satisfies the following relation,

In Equation 2, b satisfies the following relation,

는 광원의 투과도 스펙트럼이고,

는 각각 CIE 2^o Standard Observer에서 정의한 Color-matching function 이며,

는 광학 필름의 투과도 스펙트럼이다.remind

Is the transmittance spectrum of the light source,

Are color-matching functions defined in CIE 2 ^o Standard Observer, respectively.

Is the transmittance spectrum of the optical film.

Moreover, this invention provides the (meth) acrylic-type resin composition for optical film manufacture whose brightness change value ((DELTA) L) of the film before and behind an ultraviolet exposure satisfy | fills following formula (3).

In Equation 3, L satisfies the following relation,

는 광원의 투과도 스펙트럼이고,

는 CIE 2^o Standard Observer에서 정의한 Color-matching function 이며,

는 광학 필름의 투과도 스펙트럼이다.remind

Is the transmittance spectrum of the light source,

Is the color-matching function defined in CIE 2 ^o Standard Observer.

Is the transmittance spectrum of the optical film.

Moreover, this invention provides the (meth) acrylic-type resin composition for optical film manufacture whose change value ((DELTA) _EH ) of the film before and behind an ultraviolet exposure satisfy | fills following formula (4).

In Equation 4, L, a and b satisfy the following relation,

는 광원의 투과도 스펙트럼이고,

는 각각 CIE 2^o Standard Observer에서 정의한 Color-matching function 이며,

는 광학 필름의 투과도 스펙트럼이다.remind

Is the transmittance spectrum of the light source,

Are color-matching functions defined in CIE 2 ^o Standard Observer, respectively.

Is the transmittance spectrum of the optical film.

Moreover, this invention provides the optical film containing the said (meth) acrylic-type resin composition.

In addition, the present invention provides a polarizing plate and a liquid crystal display device including the optical film.

Since the optical film according to the present invention can improve the ultraviolet absorbing effect, there is an excellent characteristic that can suppress the deterioration of optical properties such as transmittance, color change of the optical film due to ultraviolet light.

Hereinafter, the present invention will be described in more detail.

The (meth) acrylic resin composition according to the present invention is characterized by satisfying the above Equation 1, Equation 2, Equation 3 or Equation 4.

When Δa of the (meth) acrylic resin composition is outside the numerical range of Equation 1, the color change in the short wavelength region is very large, so that the film may turn blue or green, and Δb is the numerical range of Equation 2 above. Outside of, the change in the long wavelength region is so large that the film may turn red or yellow.

The (meth) acrylic resin composition according to the present invention is not only excellent in transparency, optical characteristics and the like, but also can produce an optical film having excellent ultraviolet absorption effect. Therefore, the optical film may be usefully used as an optical film for various uses in a liquid crystal display device. In particular, the optical film according to the present invention can be more usefully used as a polarizer protective film.

The (meth) acrylic resin composition according to the present invention comprises an aromatic unit having a chain having an hydroxy group containing portion and an aromatic portion; And a (meth) acrylic resin including a styrene unit including at least one styrene derivative.

The content ratio of the aromatic unit and the styrene unit is preferably 65 to 75: 100 based on mol. In addition, the content ratio of the aromatic unit and the styrene unit is preferably 45 to 55: 100 based on the weight. Compositions within this range are advantageous for achieving the above-mentioned transparency, optical characteristics, ultraviolet absorbing effect and the like.

The (meth) acrylic resin may further include a (meth) acrylate-based unit including one or more (meth) acrylate-based derivatives.

In addition, the ratio of the sum of the content of the aromatic unit and the styrene unit and the content of the (meth) acrylate unit is preferably 1:99 to 50:50 based on the weight. Compositions within this range are advantageous for achieving the above-mentioned transparency, optical characteristics, ultraviolet absorbing effect and the like.

A (meth) acrylate-based unit comprising the at least one (meth) acrylate-based derivative; An aromatic unit having a chain having the hydroxy group-containing portion and an aromatic portion; And styrenic units including the one or more styrene derivatives may be included in different compounds, respectively, and two or more units of the units may be included in one compound.

In addition, the optical film produced according to the present invention has excellent mechanical properties unlike conventional brittle acrylic films. In addition, the (meth) acrylate-based unit can provide excellent optical physical properties, and the aromatic-based unit having a chain and an aromatic portion having the hydroxy group-containing portion has an excellent blend with the compound containing the (meth) acrylate-based unit. Can provide Mars.

The (meth) acrylic resin may further include a ring-based unit having a ring portion. The ring-based unit having the cyclic moiety may be included in the compound containing at least one of the (meth) acrylate-based unit, the chain having the hydroxy group-containing part and the aromatic unit having the aromatic moiety, and the styrene-based unit, ) May be included in a compound different from a compound containing at least one of an acrylate unit, a chain having an hydroxy group-containing portion and an aromatic unit having an aromatic portion, and the styrene unit. The ring-based unit having the ring portion can provide excellent heat resistance to the film.

According to the exemplary embodiment of the present invention, a copolymer including the (meth) acrylate-based unit and the ring-based unit having the ring portion, a copolymer including the (meth) acrylate-based unit and the styrene-based unit, A copolymer comprising a styrene-based unit and a ring-based unit having the cyclic moiety, the (meth) acrylate-based unit, an aromatic unit having a chain and an aromatic moiety having the hydroxy group-containing part, and a copolymer comprising the styrene-based unit Can be used. In this case, the copolymers may include two or more types of at least one of the units.

As a specific example, a copolymer comprising a (meth) acrylate-based unit such as methyl (meth) acrylate and a ring-based unit such as N-cyclohexylmaleimide, that is, poly (N-cyclohexylmaleimide-co-methyl (Meth) acrylate) can be used. It is also possible to use copolymers comprising styrenic units such as styrene and cyclic units such as maleic anhydride. Moreover, the copolymer containing methyl methacrylate as a (meth) acrylate type unit, styrene and alphamethyl styrene as a styrene unit, and N-cyclohexyl maleimide as a ring type unit can be used. In addition, a copolymer including methyl methacrylate as the (meth) acrylate-based unit, styrene or alphamethylstyrene as the styrene-based unit, and N-cyclohexylmaleimide and maleic anhydride as the ring-based unit can be used. However, the above examples are for illustrating the present invention, and the scope of the present invention is not limited to the above examples.

The content of each unit is not particularly limited, and considering the role of each of the above-described components, the content of each unit may be determined to achieve optical properties, mechanical properties, transparency, miscibility, and the like. For example, the content of the (meth) acrylate-based unit, the chain having the hydroxyl group-containing portion and the aromatic-based unit having the aromatic moiety, the styrene-based unit and the ring-based unit may be selected in the range of about 0.1 to 99% by weight, respectively. Can be. Specifically, the content of the (meth) acrylate-based unit is preferably about 50 to 98% by weight, and the content of the aromatic-based unit having a chain and an aromatic portion having the hydroxy group-containing portion is preferably about 0.5 to 40% by weight. And, the content of the styrene-based unit is preferably about 0.5 to 30% by weight. The content of the ring-based unit is preferably about 0.5 to 45% by weight.

In the present invention, the compound comprising the (meth) acrylate-based unit, the chain having the hydroxy group-containing portion and the aromatic unit having an aromatic moiety, the styrene-based unit or the ring-based unit may be a homopolymer or a copolymer And an aromatic unit, a styrene-based unit and a unit other than the cyclic-based unit having the (meth) acrylate-based unit, the chain having the hydroxy group-containing portion and the aromatic moiety within the scope of not impairing the object of the present invention. can do. The copolymer may be a random or block copolymer.

In the present invention, it should be understood that the (meth) acrylate-based unit may include (meth) acrylate as well as (meth) acrylate derivatives. Specifically, the (meth) acrylate monomers include methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and the like. It is not limited only to this. In particular, it is most preferable to use methyl methacrylate (MMA).

In the present invention, as the compound containing the (meth) acrylate-based unit, a copolymer including a (meth) acrylate-based unit and a ring-based unit having the ring portion can be used. The content of the (meth) acrylate-based unit in the copolymer including the (meth) acrylate-based unit and the cyclic-based unit having the cyclic moiety is about 50 to 99% by weight, preferably about 70 to 98% by weight, The content of the ring-based unit having the ring portion is about 1 to 50% by weight, preferably about 2 to 30% by weight. If the content of the ring-based unit having the ring portion is 50% by weight or less, it is advantageous to lower the haze value of the film.

The ring-based unit having the ring portion in the copolymer including the (meth) acrylate-based unit and the ring-based unit having the ring portion serves to improve the heat resistance of the film. Examples of the ring system unit having the ring portion will be described later. However, the ring-based unit having a ring portion included in the copolymer together with the (meth) acrylate-based unit is most preferably a maleimide unit including a maleimide portion. The maleimide-based unit may include a ring portion derived from N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-butylmaleimide, and the like, but is not limited thereto. Most preferably it comprises a ring moiety derived from cyclohexylmaleimide.

The copolymer including the (meth) acrylate-based unit and the cyclic-based unit having the cyclic moiety includes a cyclic monomer such as a (meth) acryl-based monomer and a maleimide-based monomer, and may include bulk polymerization, solution polymerization, suspension polymerization, It may be prepared by a method such as emulsion polymerization.

In the present invention, the number average molecular weight of the aromatic unit having the chain having the hydroxy group-containing portion and the aromatic moiety is preferably 1,500 to 2,000,000 g / mol. It is preferable that the said aromatic type unit contains a phenoxy clock resin. Here, the phenoxy resin includes a structure in which at least one oxygen radical is bonded to a benzene ring. For example, the aromatic unit may include one or more units represented by Formula 1 below. The aromatic unit preferably contains 5 to 10,000 units, more preferably 5 to 7,000 units, more preferably 5 to 5,000 units of the following general formula (1). When two or more units represented by the following Chemical Formula 1 are included in the aromatic unit, they may be included in the form of random, alternating or block.

In Formula 1,

  X is a divalent group comprising at least one benzene ring, and R is a straight or branched chain alkylene having 1 to 6 carbon atoms.

Specifically, X is preferably a divalent radical derived from a compound represented by the following general formulas (2) to (4), but is not limited thereto.

In Formula 2,

R ¹ is a direct bond, a straight or branched alkylene having 1 to 6 carbon atoms or a cycloalkylidene having 3 to 20 carbon atoms,

R ² and R ³ are each hydrogen, straight or branched alkyl having 1 to 6 carbon atoms or straight or branched alkenyl having 2 to 6 carbon atoms, n and m are each an integer of 1 to 5,

In Formula 3,

R ⁴ is hydrogen, straight or branched chain alkyl having 1 to 6 carbon atoms or straight or branched alkenyl having 2 to 6 carbon atoms, p is an integer of 1 to 6,

In Chemical Formula 4,

R ⁶ and R ⁷ are each a direct bond, a linear or branched alkylene having 1 to 6 carbon atoms or a cycloalkylidene having 3 to 20 carbon atoms,

R ⁵ and R ⁸ are each hydrogen, straight or branched chain alkyl having 1 to 6 carbon atoms, or straight or branched alkenyl having 2 to 6 carbon atoms, and q and r each are an integer of 1 to 5.

Specific examples of the compounds represented by the formulas (2) to (4) are shown below, but the present invention is not limited thereto.

In particular, the aromatic unit is most preferably containing 5 to 10,000 one or more phenoxy clock units represented by the following formula (5).

In the general formula (5), R ⁹ is a direct bond or a straight-chain or branched alkylene having 1 to 6 carbon atoms, and R ¹⁰ is a straight or branched alkylene having 1 to 6 carbon atoms.

The formula (5) is preferably represented by the following formula (6).

The terminal of the compound including the aromatic unit may be an OH group.

In the present invention, it should be understood that the styrene-based unit may include styrene-based derivatives as well as styrene. Styrene-based derivatives include compounds having one or more substituents containing aliphatic hydrocarbons or heteroatoms in the benzene ring or vinyl group of styrene, and specifically include alphamethyl styrene.

In the present invention, a copolymer including a styrene-based unit and a ring-based unit having the ring portion can be used as the compound containing the unit. The content of the styrene-based unit in the copolymer including the styrene-based unit and the cyclic-based unit having a ring portion is about 1 to 99% by weight, preferably about 30 to 99% by weight, more preferably about 40 to 95% by weight. And the content of the ring-based unit having a ring portion is about 1 to 99% by weight, preferably about 1 to 70% by weight, more preferably about 5 to 60% by weight. The adhesive and heat resistance of a film can be improved by melt-mixing the copolymer including the styrene-based unit and the cyclic-based unit having a ring portion. If the content of the ring-based unit having a ring portion is too small, the miscibility may be somewhat poor. Examples of the ring system unit having the ring portion will be described later. However, the ring-based unit having a ring portion included in the copolymer together with the ring-based unit is most preferably a maleic anhydride-based unit including maleic anhydride.

In the present invention, the ring-based unit can improve the heat resistance of the film. The content of the ring-based unit is about 0.1 to 99% by weight, preferably about 0.5 to 45% by weight. The ring portion of the ring-based unit includes maleic anhydride, maleimide, glutaric anhydride, glutalimide, lactone, lactam, and the like, but is not limited thereto.

According to one embodiment of the present invention, as components comprising the aforementioned units, 1) a copolymer comprising a (meth) acrylate-based unit and a maleimide-based unit, 2) a phenoxy-based unit 3) A copolymer including a resin and 3) a styrene-based unit and a maleic anhydride unit can be used. In this case, the content of each component is preferably 1 to 99% by weight. Specifically, the 1) copolymer is preferably about 50 to 99% by weight, more preferably about 75 to 98% by weight. 2) The resin is preferably about 0.5 to 40% by weight, more preferably about 1 to 30% by weight. 3) The copolymer is preferably about 0.5 to 30% by weight, more preferably about 1 to 20% by weight.

In particular, when the content of the maleimide monomer in the copolymer including the 1) (meth) acrylate-based unit and the maleimide-based unit is 50% by weight or less, regardless of the mixing ratio of the components 1) to 3) Miscibility with respect to the area can be exhibited, and optical films of this composition have an excellent advantage of exhibiting a single glass transition temperature (Tg).

The (meth) acrylic resin composition according to the present invention may further include a triazole ultraviolet absorber.

Examples of the triazole-based ultraviolet absorber include Tinuvin 360 manufactured by Ciba Chemical Co., Ltd., but are not limited thereto.

The content of the triazole-based ultraviolet absorber is preferably 0.01 to 2.0 parts by weight based on 100 parts by weight of the (meth) acrylic resin composition.

The thickness of the optical film according to the present invention is preferably 5 to 500 µm, more preferably 5 to 300 µm, but is not limited thereto.

Moreover, it is preferable that the glass transition temperature of the said optical film is 100 degreeC or more. In particular, in this invention, it is preferable that the change of the glass transition temperature before and after addition of the said triazole type ultraviolet absorber is within +/- 1 degreeC.

In addition, the transmittance at 380 nm of the optical film is 30% or less, and the transmittance at 550 nm is preferably 92% or more, but is not limited thereto.

The optical film may control the value of the photoelastic coefficient extremely small according to the content of the chain having the hydroxyl group-containing portion and the aromatic unit and the styrene unit having the aromatic portion, and in this case, the change of the phase difference value due to external stress is small. The light leakage phenomenon can be reduced.

Method for producing an optical film according to the present invention comprises the steps of preparing the above-mentioned resin composition; And molding the film using the resin composition. The method of manufacturing the optical film may further include uniaxially or biaxially stretching the film.

The resin composition may be prepared by melting and blending the aforementioned components. Melt mixing of the components may be performed using an extruder or the like.

The resin composition may further include a lubricant, an antioxidant, a UV stabilizer, a heat stabilizer, and the like, which are generally used.

In manufacturing the optical film according to the present invention, a method known in the art may be used, and in particular, an extrusion molding method may be used. For example, the resin composition is dried in vacuo to remove moisture and dissolved oxygen, and then fed from a raw material hopper to a single or twin extruder substituted with nitrogen, and melted at a high temperature to obtain raw material pellets, and vacuum drying the obtained raw material pellets, After melt | dissolving from a raw material hopper to the extruder with a nitrogen-substituted single extruder, it can pass through the coat hanger type T-die, and can manufacture a film through a chrome plating casting roll, a drying roll, etc.

In preparing the optical film according to the present invention, the method may further include uniaxially or biaxially stretching the film. 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. The stretching can be performed in one step or in multiple steps. When stretching in the longitudinal direction, stretching can be performed by the speed difference between the rolls, and in the case of stretching in the transverse direction, tenter can be used. The time of railing of the tenter is within 10 degrees of the total, suppressing the bowing phenomenon occurring in the transverse direction drawing, and controlling the angle of the optical axis regularly. It is also possible to obtain the same bowing suppression effect by setting the transverse stretching in 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 called Tg. The glass transition temperature refers to a range from a temperature where the storage elastic modulus of the resin composition begins to decrease and a loss elastic modulus becomes larger than a storage elastic modulus to a temperature at which the orientation of the polymer chain is relaxed and disappears. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

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 stretching may proceed as a separate step from the forming of the film, or may be carried out in one step in the same process as the forming of the film.

The composition and the longitudinal stretching ratio, the transverse stretching ratio, the stretching temperature and the stretching speed of each of the above-described units can be appropriately combined.

In addition, the stretched film can effectively compensate for the disadvantages of the brittle (meth) acrylate-based film because the toughness is increased.

In addition, the present invention provides a polarizer including a polarizer and the optical film provided on at least one surface of the polarizer.

Since a polarizer consists of a uniaxially stretched polyvinyl alcohol film containing a dichroic dye, since it is inferior to temperature or moisture, it is laminated by a protective film. Conventionally, the liquid crystal display device which has a polarizing plate has been mainstream in which a clock, an instrument panel, etc. are comparatively small in area, or performed the anti-reflective process of the light-diffusion system to the surface. The use of the recent liquid crystal display device is a large display area such as a large screen display, or a low haze antireflection treatment such as a glossy surface on a surface by a multilayer interference method. In this case, defects such as streaks, bends, scratches, and contamination occurring on the surface of the protective film for polarizing plates become noticeable, which is mainly due to the fact that the protective film for polarizing plates of the mainstream currently uses a triacetyl cellulose film.

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, the stretching process is required at high temperature, and the optical elastic modulus of the film is large, resulting in 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 polarizer protective film according to the present invention may be provided only on one surface of the polarizer, or may be provided on both sides.

When the polarizer protective film according to the present invention is provided only on one surface of the polarizer, the other surface may be provided with a protective film known in the art. The known protective film includes a triacetate cellulose (TAC) film, a polynorbornene-based film made of ring opening metathesis polymerization (ROMP), and a HROMP obtained by hydrogenating a ring-opening polymerized cyclic olefin-based polymer again. (ring opening metathesis polymerization followed by hydrogenation) may be a polymer film, a polyester film, or a polynorbornene-based film prepared by addition polymerization. In addition, a protective film or the like made of a transparent polymer material may be used, but is not limited thereto.

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

In the present invention, the protective film and the polarizer may be laminated by a method known in the art.

In addition, the present invention provides a liquid crystal display device including the polarizing plate. For example, the liquid crystal display according to the present invention is a liquid crystal display including a liquid crystal cell and a first polarizing plate and a second polarizing plate respectively provided on both surfaces of the liquid crystal cell, wherein at least one of the first polarizing plate and the second polarizing plate is It is characterized in that the polarizing plate according to the present invention.

It is preferable that the polarizer protective film provided on the opposite side to the liquid crystal cell of the said polarizing plate contains a UV absorber.

In addition, the present invention provides a liquid crystal display device including the optical film.

In one embodiment, the liquid crystal display according to the present invention is a liquid crystal display comprising a liquid crystal cell and a first polarizing plate and a second polarizing plate respectively provided on both sides of the liquid crystal cell, wherein the first polarizing plate and the second polarizing plate An optical film according to the present invention may be provided between at least one of the liquid crystal cells.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention by the following examples.

< Example >

< Example  1>

As poly (N-cyclohexylmaleimide-co-methylmethacrylate) resin, IH830HR resin manufactured by LGMMA was used. As the phenoxy resin, phenoxy resin InChemRez Phenoxy PKFE® resin of InChem Corporation was used, and DYLARK® 332 (85 wt% of styrene and 15 wt% of maleic anhydride) of NOVA Chemicals was used as the styrene-maleic anhydride copolymer resin. . Tinuvin 360, a triazole system of Ciba Chemical Company, was used as the ultraviolet absorber.

0.6 parts by weight of Tinuvin 360 based on 100 parts by weight of a composition including 100 parts by weight of poly (N-cyclohexylmaleimide-co-methylmethacrylate), 3 parts by weight of styrene-maleic anhydride copolymer resin and 5 parts by weight of phenoxy resin. The mixture was uniformly mixed, and then dried in vacuo to remove moisture and dissolved oxygen, and then supplied to an extruder of 24φ substituted with nitrogen from the raw material hopper to the extruder, and melted at 250 ° C. to prepare a raw material pellet.

The pellets were vacuum dried and the glass transition temperature was measured at 10 ° C. per minute at elevated rate under a nitrogen atmosphere using a differential scanning calorimeter (Mettler Toledo, DSC823).

The obtained raw material pellets were vacuum dried, then fed from an raw material hopper to a twin extruder substituted with nitrogen, melted with an extruder at 260 ° C., passed through a T-die of a coat hanger type, and a chrome plated casting roll and The film of 120 micrometers in thickness was produced through the drying roll.

< Example  2>

Specimen was prepared in the same manner as in Example 1 except that Tinuvin 360 contained 0.9 parts by weight.

< Example  3>

Specimen was prepared in the same manner as in Example 1 except that 1.3 parts by weight of Tinuvin 360 was included.

The optical film prepared in Examples 1 to 3 was held at 120 ° C. for 2 minutes using a biaxial stretching machine, and then stretched at 40% in the MD direction and 60% in the TD direction to prepare a stretched film having a thickness of 60 μm. .

The optical film obtained by extending | stretching was irradiated with ultraviolet-ray for 500 hours by the intensity | strength of 0.6 W / m <^2> at the temperature of 60 degreeC using the ultraviolet exposure test apparatus (UV2000, Atlas). The transmittance and color of the prepared film were measured using a spectrophotometer (n & k spectrometer, n & k Technology).

Transmittance and color were measured by n & k as physical properties of the optical films according to Examples 1 to 3, and are shown in Table 1 below, and the optical properties before and after the ultraviolet exposure of the optical film were measured and shown in Table 2 below.

< Comparative Example  1>

A film was prepared in the same manner as in Example 1, except that no ultraviolet absorbent was prescribed.

< Comparative Example  2>

A 60 µm TD TAC film manufactured by Fuji was used.

The films of Comparative Examples 1 and 2 were shown in Table 1 by measuring the transmittance and color by n & k as in Examples 1 to 3, and the changes in optical properties before and after UV exposure of the film were shown in Table 2 below.

SAMPLE Tg (占 폚) % T @ 380nm % T @ 550nm a b Example 1 Tinuvin 360
0.6 parts by weight 120 30 92 -0.2 0.3 Example 2 Tinuvin 360
0.9 parts by weight added 119 20 92 -0.2 0.3 Example 3 Tinuvin 360
1.3 parts by weight 119 9 92 -0.2 0.3 Comparative Example 1 UV absorbers
No addition 120 90 92 -0.1 0.2 Comparative Example 2 TAC film - 3 92 -0.3 0.5

SAMPLE ΔL Δa Δb ΔE _H Example 1 Tinuvin 360
0.6 parts by weight 0.08 -0.1 0.3 0.3 Example 2 Tinuvin 360
0.9 parts by weight added 0.08 0.0 0.2 0.2 Example 3 Tinuvin 360
1.3 parts by weight 0.04 0.0 0.1 0.1 Comparative Example 1 UV absorbers
No addition -0.13 -0.3 1.0 1.0 Comparative Example 2 TAC film 0.04 -0.1 0.4 0.4

As can be seen through the results of Examples 1 to 3 and Comparative Examples 1 to 2, it can be seen that the optical film according to the present invention has little change in transmittance, color, brightness, etc. before and after ultraviolet exposure.

<Comparative Examples 3 to 8>

A film was prepared in the same manner as in Example 1 except that the sample shown in Table 3 was used. And as shown in Examples 1 to 3, and measured the transmittance and color in n & k shown in Table 3 below, after irradiating the ultraviolet ray to the film for 144 hours and the change in optical properties before and after exposure is shown in Table 4 below. As a result, it can be seen that there is a large change in the optical properties even in the exposure treatment of only 144 hours, which is a short time compared to the 500 hours UV irradiation in Examples 1 to 3.

SAMPLE Tg (占 폚) % T @ 380nm % T @ 550nm a b Comparative Example 3 UV1164
0.2 parts by weight - 69 92 -0.2 0.2 Comparative Example 4 UV1164
0.6 parts by weight - 72 92 -0.1 0.2 Comparative Example 5 UV1164
1.0 parts by weight added - 68 92 -0.1 0.3 Comparative Example 6 Tinuvin1577
0.2 parts by weight - 60 92 -0.1 0.3 Comparative Example 7 Tinuvin1577
0.6 parts by weight - 65 92 -0.2 0.5 Comparative Example 8
Tinuvin1577
1.0 parts by weight added - 60 92 -0.2 0.3

[Change amount after 144 hours UV exposure] SAMPLE ΔL Δa Δb ΔE _H Comparative Example 3 UV1164
0.2 parts by weight 0.00 -0.1 0.2 0.2 Comparative Example 4 UV1164
0.6 parts by weight -0.10 -0.1 0.1 0.2 Comparative Example 5 UV1164
1.0 parts by weight added 0.1 -0.1 0.2 0.3 Comparative Example 6 Tinuvin1577
0.2 parts by weight -0.16 -0.1 0.2 0.3 Comparative Example 7 Tinuvin1577
0.6 parts by weight -0.10 0.0 0.1 0.1 Comparative Example 8 Tinuvin1577
1.0 parts by weight added -0.16 0.0 0.1 0.2

Claims (19)

(Meth) acrylic resin composition for optical film production, wherein the color change values (Δa, Δb) of the films before and after ultraviolet exposure satisfy the following formulas (1) and (2), respectively:
[Equation 1]

&Quot; (2) &quot;

In Equation 1, a satisfies the following relation,

In Equation 2, b satisfies the following relation,

remind

Is the transmittance spectrum of the light source,

Are color-matching functions defined in CIE 2 ^o Standard Observer, respectively. Is the transmittance spectrum of the optical film. The (meth) acrylic resin composition for optical film production according to claim 1, wherein the change value (ΔE _H ) of the film before and after ultraviolet exposure satisfies the following formula (4):
&Quot; (4) &quot;

In Equation 4, Δa and Δb denote color change values and ΔL denote brightness changes, respectively, and L, a, and b satisfy the following relations,

remind

Is the transmittance spectrum of the light source,

Are color-matching functions defined in CIE 2 ^o Standard Observer, respectively.

Is the transmittance spectrum of the optical film. (Meth) acrylic-type resin composition for optical film manufacture whose change value ((DELTA) _EH ) of the film before and behind an ultraviolet exposure satisfy | fills following formula (4):
&Quot; (4) &quot;

In Equation 4, Δa and Δb denote color change values and ΔL denote brightness changes, respectively, and L, a, and b satisfy the following relations,

remind

Is the transmittance spectrum of the light source,

Are color-matching functions defined in CIE 2 ^o Standard Observer, respectively.

Is the transmittance spectrum of the optical film. The (meth) acrylic resin composition for optical film production according to claim 1, wherein the brightness change value (ΔL) of the film before and after ultraviolet exposure satisfies the following formula (3):
&Quot; (3) &quot;

In Equation 3, L satisfies the following relation,

remind

Is the transmittance spectrum of the light source,

Is the color-matching function defined in CIE 2 ^o Standard Observer.

Is the transmittance spectrum of the optical film. The (meth) acrylic resin composition for optical film production according to claim 2, wherein the brightness change value (ΔL) of the film before and after ultraviolet exposure satisfies the following formula (3):
&Quot; (3) &quot;

In Equation 3, L satisfies the following relation,

remind

Is the transmittance spectrum of the light source,

Is the color-matching function defined in CIE 2 ^o Standard Observer.

Is the transmittance spectrum of the optical film. The (meth) acrylic resin composition for optical film production according to claim 3, wherein the brightness change value (ΔL) of the film before and after ultraviolet exposure satisfies the following expression (3):
&Quot; (3) &quot;

In Equation 3, L satisfies the following relation,

remind

Is the transmittance spectrum of the light source,

Is the color-matching function defined in CIE 2 ^o Standard Observer.

Is the transmittance spectrum of the optical film. The (meth) acrylic resin composition according to any one of claims 1 to 6, wherein the (meth) acrylic resin composition comprises an aromatic unit having a chain having an hydroxy group-containing portion and an aromatic portion; And (meth) acrylic resins comprising a styrene-based unit comprising at least one styrene-based derivative. The (meth) acrylic resin for manufacturing an optical film according to claim 7, wherein the (meth) acrylic resin composition further includes a (meth) acrylate-based unit including at least one (meth) acrylate-based derivative. Composition. The (meth) acrylic resin composition for manufacturing an optical film according to claim 7, wherein the (meth) acrylic resin composition further includes a ring-based unit having a ring portion. The (meth) acrylic resin composition for manufacturing an optical film according to claim 7, wherein the aromatic unit comprises a phenoxy resin. The (meth) acrylic resin composition for manufacturing an optical film according to claim 7, wherein the aromatic unit comprises 5 to 10,000 at least one unit represented by the following Chemical Formula 1.
[Formula 1]

In Formula 1, X is a divalent group including at least one benzene ring, and R is a straight or branched chain alkylene group having 1 to 6 carbon atoms. The method according to claim 8, wherein the (meth) acrylate-based unit is a copolymer of a (meth) acrylate derivative and maleimide, the aromatic unit comprises 5 to 10,000 units represented by the formula (6), the styrene-based The (meth) acrylic resin composition for producing an optical film, wherein the unit is a copolymer of a styrene derivative and maleic anhydride:
[Chemical Formula 6]

The (meth) acrylic resin composition for manufacturing an optical film according to claim 7, wherein the (meth) acrylic resin composition further includes a triazole ultraviolet absorber. The (meth) acrylic resin composition for manufacturing an optical film according to claim 13, wherein the content of the triazole ultraviolet absorber is 0.01 to 2.0 parts by weight based on 100 parts by weight of the (meth) acrylic resin composition. The optical film containing the (meth) acrylic-type resin composition for optical film manufacture of any one of Claims 1-6. The optical film according to claim 15, wherein the transmittance at 380 nm of the optical film is 30% or less, and the transmittance at 550 nm is 92% or more. The said optical film is for polarizing plate protective films, The optical film of Claim 15 characterized by the above-mentioned. A polarizing plate comprising a polarizer and the optical film of claim 15 provided on at least one surface of the polarizer. A liquid crystal display device comprising the polarizing plate of claim 18.