KR20160049506A - (meth)acrylic resin - Google Patents

Abstract

(I): wherein R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents a cyclic structure, and a repeating unit represented by the formula (II): , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms) (Meth) acrylic resin containing a (meth) acrylic resin having a repeating unit.

Description

(Meth) acrylic resin {(METH) ACRYLIC RESIN}

The present invention relates to a (meth) acrylic resin. More specifically, the present invention relates to a protective film for optical disc substrates such as VD, CD, DVD, MD and LD, a polarizer protective film for use in a polarizing plate provided in an image display apparatus such as a liquid crystal display An optical film represented by a protective film for optical such as a film, an antireflection film used for an organic EL display (OLED), a transparent conductive film formed with a transparent conductive layer such as an ITO layer, an image display device on which the optical film is mounted, And a (meth) acrylic resin which can be preferably used as a raw material of the optical film.

In recent years, development of an optical material having a high optical characteristic has been demanded in an image display device due to a demand for improvement of sharpness of an image. As one of the high optical characteristics, a birefringence is required to be small. Generally, in a polymer compound used as an optical material, birefringence occurs because the refractive index of the molecule in the main chain direction is different from that in the direction perpendicular to the main chain direction. A cellulose resin such as triacetyl cellulose has been proposed as a polymer material for an optical film having a small birefringence (see, for example, Patent Document 1).

However, the optical film made of a cellulose-based resin has a drawback that a phase difference is generated with respect to incident light in an oblique direction, and a retardation with respect to the incident light in the oblique direction adversely affects the viewing angle characteristic in a large liquid crystal display.

On the other hand, polymethylmethacrylate has been conventionally proposed as an optical material having excellent molding processability, high surface hardness, high light transmittance, low birefringence and low wavelength dependency (see, for example, Patent Document 2). However, since polymethyl methacrylate has a low glass transition temperature (Tg) of about 100 DEG C, it is inferior in heat resistance and, therefore, it is difficult to use in polymethyl methacrylate for applications requiring heat resistance, for example, in image display devices.

Therefore, as a method for improving the heat resistance of an acrylic resin such as polymethyl methacrylate, when an optical film is molded by extrusion molding of an acrylic resin by using an extruder, an acrylic resin is treated with methylamine, (See, for example, Patent Document 3). However, a resin obtained by imidizing an acrylic resin with methylamine has a drawback that the birefringence is large.

Japanese Patent Application Laid-Open No. 2009-265174 Japanese Patent Application Laid-Open No. 06-102547 Japanese Patent Application Laid-Open No. 2009-107180

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior arts, and an object of the present invention is to provide a (meth) acrylic resin which can be preferably used as a raw material for an optical film having excellent heat resistance, small birefringence, high surface hardness and small photoelastic coefficient, A transparent conductive film on which a transparent conductive layer such as an ITO layer is formed by using the (meth) acrylic resin, and an image display device on which the optical film is mounted.

The present invention

(1) Formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents a cyclic structure)

And a repeating unit represented by the formula (II):

(Wherein R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms)

 (Meth) acrylic resin having a repeating unit represented by the following formula

(2) The (meth) acrylic resin according to the above (1), which has 5 to 85% by weight of the repeating unit represented by the formula (I) and 15 to 95% by weight of the repeating unit represented by the formula (II) Suzy,

(3) a (meth) acrylic resin according to the above (1) or (2) having a glass transition temperature of 120 ° C or higher,

(4) (meth) acrylic resin as described in any one of the absolute value of the optical system can stress ^{(Cr) 0.3 × 10 -9 ㎩} -1 or less of (1) to (3),

(5) A process for producing a (meth) acrylic resin according to any one of (1) to (4) above, which imidizes a (meth) acrylic resin having a repeating unit represented by the formula (II)

(6) An optical film comprising the (meth) acrylic resin according to any one of (1) to (4)

(7) The optical film according to (6) above, wherein the in-plane retardation (Re) at a wavelength of 590 nm is 20 nm or less and the absolute value of the retardation in the thickness direction (Rth)

8 wavelength the absolute value of the photoelastic coefficient with respect to light of 10 × 10 ^-12 590㎚ ㎩ ^-1 or less the optical film according to (6) or (7),

(9) The optical film according to any one of (6) to (8), wherein the coefficient of linear expansion at 60 to 100 ° C is 80 × 10 ^-6 K ^-1 or less,

(10) The optical film according to any one of (6) to (9), which is a biaxially oriented film,

(11) A transparent conductive film comprising a transparent conductive layer formed on at least one surface of the optical film according to any one of (6) to (10)

(12) An image display apparatus having the optical film according to any one of (6) to (10) above, and

(13) An image display device having the transparent conductive film according to (11)

.

In the present specification, "(meth) acrylic" means "acrylic" or "methacryl".

(Effects of the Invention)

(Meth) acrylic resin, an optical film using the (meth) acrylic resin, an optical film using the (meth) acrylic resin, and the like can be preferably used as raw materials for an optical film having a high heat resistance and a small birefringence, A transparent conductive film on which a transparent conductive layer such as an ITO layer is formed using a (meth) acrylic resin, and an image display device on which the optical film is mounted.

As described above, the (meth) acrylic resin of the present invention has the formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents a cyclic structure)

And a repeating unit represented by the formula (II):

(Wherein R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms)

As a repeating unit.

In the repeating unit represented by formula (I), R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert- An isohexyl group, an n-heptyl group, an isoheptyl group, an n-octyl group, and a 2-ethylhexyl group, but the present invention is not limited to these examples. Of these, R ¹ and R ² are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms from the viewpoint of obtaining an optical film excellent in heat resistance and having a small birefringence.

In the repeating unit represented by the formula (I), R ³ represents a cyclic structure. Examples of the ring structure include a cycloalkyl group having 3 to 12 carbon atoms and an aryl group having 6 to 10 carbon atoms. Examples of the cycloalkyl group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group, but the present invention is not limited to these examples. Among these cycloalkyl groups, a cycloalkyl group having 3 to 6 carbon atoms is preferable from the viewpoint of obtaining an optical film excellent in heat resistance and having a small birefringence, and a cyclohexyl group is more preferable. Examples of the aryl group having 6 to 10 carbon atoms include phenyl group, benzyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,3- Naphthyl group, binaphthyl group, anthryl group and the like can be given. However, the number of the The invention is not limited to these examples. Among these aryl groups, a phenyl group and a tolyl group are preferable from the viewpoint of obtaining an optical film excellent in heat resistance and having a small birefringence. Among R ³ , a cycloalkyl group having 3 to 6 carbon atoms, a phenyl group and a tolyl group are preferable, and a cyclohexyl group and a phenyl group are more preferable from the viewpoint of obtaining an optical film excellent in heat resistance and small in birefringence.

From the viewpoint of obtaining an optical film having excellent heat resistance and small birefringence in the repeating unit represented by the formula (I), R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom or a methyl group , And R < ³ > is preferably a cyclohexyl group or a phenyl group, preferably a phenyl group.

The (meth) acrylic resin may contain two or more kinds of repeating units represented by the formula (I).

In the repeating unit represented by the formula (II), R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert- An isohexyl group, an n-heptyl group, an isoheptyl group, an n-octyl group, and a 2-ethylhexyl group, but the present invention is not limited to these examples. Among these alkyl groups, an alkyl group having 1 to 4 carbon atoms is preferable from the viewpoint of obtaining an optical film excellent in heat resistance, small in birefringence, high in surface hardness and small in photoelastic coefficient.

In the repeating unit represented by the formula (II), R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Examples of the alkyl group having 1 to 18 carbon atoms include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, A decyl group, a dodecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group, but the present invention is not limited to these examples. Examples of the cycloalkyl group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group, but the present invention is not limited to these examples. Examples of the aryl group having 6 to 10 carbon atoms include phenyl group, benzyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,3- Naphthyl group, binaphthyl group, anthryl group and the like can be given. However, the number of the The invention is not limited to these examples. Of these, an alkyl group having 1 to 18 carbon atoms is preferable, an alkyl group having 1 to 8 carbon atoms is more preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, and an alkyl group having 1 to 8 carbon atoms is preferable from the viewpoint of obtaining an optical film having excellent heat resistance, small birefringence, high surface hardness, , And still more preferably a methyl group, an ethyl group and an n-butyl group.

R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, a n-butyl group, More preferably a hydrogen atom or a methyl group, and R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms An aryl group, preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably a methyl group, an ethyl group and an n-butyl group.

The (meth) acrylic resin may contain two or more kinds of repeating units represented by the formula (II).

The content of the repeating unit represented by the formula (I) in the (meth) acrylic resin preferably improves the heat resistance and transparency of the (meth) acrylic resin and is preferably 5 wt% More preferably not less than 10% by weight, more preferably not less than 15% by weight, from the viewpoint of improving the formability into a film to improve the mechanical strength and obtaining an optical film having a small birefringence, Or less, more preferably 80 wt% or less, and further preferably 75 wt% or less.

The content ratio of the repeating unit represented by the formula (II) in the (meth) acrylic resin is preferably 15% or more from the viewpoint of obtaining the optical film having a small birefringence, From the viewpoint of improving the heat resistance and transparency of the (meth) acrylic resin and obtaining an optical film having a small birefringence, it is preferably 95% or more, more preferably 20% By weight or less, more preferably 90% by weight or less, and still more preferably 85% by weight or less.

The (meth) acrylic resin may contain repeating units represented by the formula (I) and repeating units other than the repeating units represented by the formula (II), such as styrene units, within a range that does not impair the object of the present invention May be included. For example, when the repeating unit other than the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) is a styrene unit, the content of the styrene unit in all the repeating units is preferably 10% More preferably 5% by weight or less, further preferably 2% by weight or less, still more preferably 1% by weight or less.

From the viewpoint of improving the mechanical strength of the film, the weight average molecular weight of the (meth) acrylic resin is preferably 10000 or more, more preferably 30,000 or more, and preferably 500000 or less Preferably 300,000 or less.

In the present specification, the weight average molecular weight of the (meth) acrylic resin is a value obtained by gel permeation chromatography (GPC) under the following conditions.

System: Tosoh Corporation, Product name: GPC system HLC-8220

Development solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., limited edition)

Solvent flow rate: 0.6 ml / min

Standard sample: TSK standard polystyrene (trade name: PS-oligomer kit, manufactured by Tosoh Corporation)

Measurement side column configuration: TSK-GEL super HZ-L (product name: TSK-GEL super HZM-M 6.0 × 150, two serial connection, TSK-GEL super HZ- Use dog]

Composition of the reference side column: Reference column (trade name: TSK-GEL SuperH-RC 6.0 × 150, two serial connection)

· Column temperature: 40 ° C

The glass transition temperature of the (meth) acrylic resin is preferably 120 deg. C or more, more preferably 130 deg. C or more, further preferably 140 deg. C or more, still more preferably 150 deg. C or more from the viewpoint of improving the heat resistance of the film . The glass transition temperature of the (meth) acrylic resin is preferably 250 占 폚 or lower, more preferably 230 占 폚 or lower, still more preferably 210 占 폚 or lower, and still more preferably, 200 ° C or less.

In the present specification, the glass transition temperature of the (meth) acrylic resin is a value obtained in accordance with JIS K7121. More specifically, using a differential scanning calorimeter (trade name: Thermo plus EVO DSC-8230, manufactured by Rigaku Corporation) and using a-alumina as a reference, about 10 mg of a (meth) acrylic resin From a room temperature to 200 ° C at a heating rate of 20 ° C / min.

The acid value of the (meth) acrylic resin is preferably 1.4 mmol / g or less, more preferably 0.8 mmol / g or less, still more preferably 0.5 mmol / g or less, from the viewpoint of improving moldability, g or less, and still more preferably 0.3 mmol / g or less. Acid value of the (meth) acrylic resin is a value measured based on the method described in the following examples.

The absolute value of the stress optical coefficient (Cr) of the (meth) acrylic resin is preferably in the range of 0.3 x 10 < ^-9 > Pa ^-1 or less, more preferably 0.2 x 10 ^-9 Pa ^-1 or less, and further preferably 0.1 x 10 ^-9 Pa ^-1 or less. The stress optical coefficient (Cr) of the (meth) acrylic resin is a value measured by the method described in the following examples.

Further, by controlling the absolute value of the stress optical coefficient (Cr) of the (meth) acrylic resin to be 0.3 x 10 < ^-9 > Pa- ¹ or less, the absolute value of the thickness direction retardation (Rth) 20 nm or less.

The (meth) acrylic resin can be obtained, for example, by imidizing a (meth) acrylic resin having a repeating unit represented by the formula (II) with an imidization agent. (Meth) acrylic resin having a repeating unit represented by the formula (II) [hereinafter simply referred to as " (meth) acrylic resin "

(Wherein R ⁴ , R ⁵ and R ⁶ are as defined above)

By polymerizing a monomer represented by the following general formula (1). The monomer represented by the formula (III) may contain other monomers within the range in which the object of the present invention is not impaired. For example, when (meth) acrylic acid is used as the other monomer, the monomer represented by the formula (III) may contain (meth) acrylic acid at a content of 45% by weight or less, preferably 40% by weight or less.

Examples of the monomer represented by the formula (III) include alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group, cycloalkyl (meth) acrylates having 3 to 12 carbon atoms in the cycloalkyl group, (Meth) acrylate. These (meth) acrylates may be used alone or in combination of two or more.

Examples of the alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, (Meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl , Octadecyl (meth) acrylate, and the like, but the present invention is not limited to these examples. Examples of the cycloalkyl (meth) acrylate having 3 to 12 carbon atoms in the cycloalkyl group include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl Acrylate, and the like. However, the present invention is not limited to these examples. Examples of the aryl (meth) acrylate having 6 to 10 carbon atoms in the aryl group include phenyl (meth) acrylate, benzyl (meth) acrylate, o-tolyl (meth) acrylate, m- (Meth) acrylate, 2,5-xylyl (meth) acrylate, 2,6-xylyl (meth) acrylate, (Meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, Acrylate, binaphthyl (meth) acrylate, anthryl (meth) acrylate, and the like. However, the present invention is not limited to these examples. These (meth) acrylates may be used alone or in combination of two or more.

Examples of the method for polymerizing the monomer represented by the formula (III) include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method and a suspension polymerization method, but the present invention is not limited to these examples.

As a method for imidizing a (meth) acrylic resin to an imidization agent, for example, a known imidation method and the like can be given. As a specific method for imidizing (meth) acrylic resin into an imidization agent, for example,

(1) dissolving the (meth) acrylic resin in a solvent capable of dissolving the (meth) acrylic resin and inert to the imidization, adding an imidizing agent to the obtained (meth) acrylic resin solution, (Imide reaction method) in which imidization is carried out with an imidizing agent by reacting a (meth) acrylic resin with an imidizing agent,

(2) a method of imidizing a (meth) acrylic resin by melt-kneading a (meth) acrylic resin with an imidizing agent by adding an imidizing agent to the (meth) acrylic resin in a molten state using an extruder or the like

And the like, but the present invention is not limited to these examples.

In the batch reaction method, a batch type reaction vessel (pressure vessel) can be used. The batch type reaction vessel (pressure vessel) preferably has a structure in which a solution in which a (meth) acrylic resin is dissolved in a solvent can be heated and stirred, and an imidizing agent can be added. Since the viscosity of the solution may be increased, it is more preferable that the stirring efficiency is excellent. Examples of the batch type reaction vessel (pressure vessel) include a stir bar of Max Blend (registered trademark) made by Sumitomo Heavy Industries, Ltd., but the present invention is not limited to these examples.

Examples of the solvent which is inert to the imidization in the batch reaction method include aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol; Aromatic compounds such as benzene, toluene, xylene, chlorobenzene, and chlorotoluene; Ether compounds, and the like. However, the present invention is not limited to these examples. These solvents may be used alone or in combination of two or more. Of these solvents, toluene and a mixed solvent of toluene and methanol are preferred.

In the batch reaction method, the reaction temperature at the time of reacting the (meth) acrylic resin with the imidizing agent is such that the (meth) acrylic resin is imidized efficiently with the imidization agent, and the Is preferably from 160 to 400 占 폚, more preferably from 180 to 350 占 폚, and still more preferably from 200 to 300 占 폚, from the viewpoint of suppressing the decomposition, coloring and the like of the (meth) acrylic resin.

In the melt kneading method, an extruder can be used. Examples of the extruder include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder, but the present invention is not limited to these examples. Among these extruders, a biaxial extruder is preferable in that the (meth) acrylic resin and the imidizing agent can be efficiently mixed. As the twin-screw extruder, for example, there can be mentioned a non-meshing type co-rotating type twin screw extruder, an engaging type co-rotating type twin screw extruder, a non-engaging type twisting type twin screw extruder, and an engaging type twin screw type twin screw extruder , But the present invention is not limited to these examples. Each of these extruders may be used alone or two or more of them may be connected in series. Among the twin-screw extruders, the intermeshing co-rotating twin-screw extruder is preferable because it can rotate at a high speed and efficiently mix the (meth) acrylic resin and the imidizing agent.

In the above-mentioned melt-kneading method, imidization of the (meth) acrylic resin can be carried out, for example, by introducing a (meth) acrylic resin through a raw material feeding portion of an extruder, filling the cylinder with the (meth) acrylic resin, Or by injecting the deoxidizer into an extruder by means of an addition pump.

In the melt-kneading method, the temperature (resin temperature) of the reaction zone in the extruder is preferably 180 占 폚 or higher from the viewpoint of efficiently progressing the imidization reaction of the (meth) acrylic resin and improving the chemical resistance and heat resistance More preferably 220 deg. C or higher, preferably 380 deg. C or lower, more preferably 350 deg. C or lower, further preferably 350 deg. C or lower from the viewpoints of suppressing decomposition of the (meth) acrylic resin and improving the bending resistance of the optical film Lt; / RTI > The reaction zone in the extruder means a region between the injection position of the imidizing agent and the resin discharge port (die portion) in the cylinder of the extruder.

In the melt kneading method, imidization of the (meth) acrylic resin can be promoted by lengthening the reaction time of the (meth) acrylic resin and the imidizing agent in the reaction zone in the extruder. The time required for imidization of the (meth) acrylic resin in the reaction zone in the extruder is preferably 10 seconds or more, more preferably 30 seconds or more, from the viewpoint of sufficiently imidizing the (meth) acrylic resin. The pressure of the (meth) acrylic resin in the extruder is preferably not less than the atmospheric pressure, more preferably not less than 1 MPa, from the viewpoint of improving the solubility of the imidization agent, preferably not more than 50 MPa in consideration of the pressure resistance of the extruder, More preferably 30 MPa or less.

In the extruder, it is preferable to provide a vent in the extruder that can lower the pressure to atmospheric pressure or below to remove unreacted imidization agents and by-products. The number of vents may be one or plural.

In the case of imidizing the (meth) acrylic resin by the melt kneading method, for example, a transverse biaxial reaction apparatus (manufactured by Sumitomo Chemical Co., Ltd., trade name: Biovolak) A reaction apparatus capable of coping with a high viscosity such as a super-blend (manufactured by Sumitomo Chemical Co., Ltd., product name: Super Blend) can be used.

Examples of the imidization agent include cycloalkylamines having a cycloalkyl group having 3 to 12 carbon atoms such as cyclohexylamine and arylamines having 6 to 10 carbon atoms such as aniline, benzylamine, toluidine, trichloroaniline, and the like. However, the present invention is not limited to these examples. These imidization agents may be used alone or in combination of two or more. Of the imidization agents, cyclohexylamine, aniline and toluidine are preferable from the viewpoint of obtaining an optical film excellent in heat resistance and having a small birefringence, and aniline is more preferable.

Since the amount of the imidizing agent varies depending on the content of the repeating unit represented by the formula (I) and the content of the repeating unit represented by the formula (II) in the (meth) acrylic resin to be obtained, It is preferable that the (meth) acrylic resin is adjusted so that the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) are contained at a predetermined content. In other words, the content of the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) in the (meth) acrylic resin can be easily adjusted by controlling the amount of the imidizing agent.

(Meth) acrylic resin having a repeating unit represented by the formula (I) and a repeating unit represented by the formula (II) can be obtained by imidizing the (meth) acrylic resin with the imidizing agent as described above.

Further, when a (meth) acrylic resin is imidized with an imidization agent, a carboxyl group or an acid anhydride group may be produced as a by-product. Depending on the conditions for imidization, a large amount of a carboxyl group or an acid anhydride group may remain in the (meth) acrylic resin. When the carboxyl group or the acid anhydride group remains in the (meth) acrylic resin, the viscosity of the (meth) acrylic resin increases, so that there is a possibility that the molding processability when filming or the like is lowered. Further, under the moist heat condition, the hydrolysis of the acid anhydride group proceeds and the durability of the resin and the film may be lowered.

Therefore, it is preferable to convert the carboxyl group and the acid anhydride group contained in the (meth) acrylic resin into an ester. As a method for converting a carboxyl group and an acid anhydride group contained in a (meth) acrylic resin into an ester, there may be mentioned, for example, a method of converting the ester into the ester disclosed in U.S. Patent No. 4727117. However, It is not.

As a specific method for esterifying the (meth) acrylic resin with an esterifying agent, for example, in the same manner as the method of imidizing the (meth) acrylic resin with an imidizing agent,

(1) A process for producing a (meth) acrylic resin by dissolving the (meth) acrylic resin in a solvent which is capable of dissolving the (meth) acrylic resin and is inert to the esterification and then adding an esterifying agent to the obtained A method of esterifying a (meth) acrylic resin with an esterifying agent by reacting an esterifying agent (batch reaction method),

(2) a method (melt-kneading method) of esterifying (meth) acrylic resin by reacting a (meth) acrylic resin with an esterifying agent by adding an esterifying agent to the (meth) acrylic resin in a molten state using an extruder or the like,

And the like, but the present invention is not limited to these examples.

Examples of the esterifying agent include dimethyl carbonate, 2,2-dimethoxypropane, dimethylsulfoxide, triethylorthoformate, trimethylorthoacetate, trimethylorthoformate, diphenylcarbonate, dimethylsulfate, methyltoluenesulfonate, methyl Methyl isocyanate, p-chlorophenyl isocyanate, dimethyl carbodiimide, dimethyl-tert-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, (Trimethylsilane) phosphite, trimethylphosphite, trimethylphosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexene oxide, 2-ethyl Hexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, And lysedyl ether. However, the present invention is not limited to these examples. These esterifying agents may be used alone or in combination of two or more. Among the esterifying agents, dimethyl carbonate is preferred from the viewpoint of reducing the cost and preventing adverse effects such as coloration of the (meth) acrylic resin.

The amount of the esterifying agent per 100 parts by weight of the (meth) acrylic resin is usually 0 to 32 parts by weight, and more preferably 0 to 16 parts by weight.

Further, the esterifying agent can be used in combination with the catalyst. Examples of the catalyst include an aliphatic tertiary amine such as trimethylamine, triethylamine and tributylamine, and a base catalyst such as diazabicyclo-undecene and diazabicyclo- nonenene. However, the present invention is not limited to these examples But is not limited thereto. These catalysts may be used alone or in combination of two or more. Of these catalysts, diazabicycloundecene is preferred from the viewpoint of reducing the cost and preventing adverse effects such as coloration of the (meth) acrylic resin. The amount of the catalyst is not particularly limited, but is usually 0 to 10 parts by weight, more preferably 0 to 5 parts by weight, and more preferably 0 to 2 parts by weight per 100 parts by weight of the (meth) acrylic resin.

Generally, a glutarimide resin is obtained by imidizing a (meth) acrylic resin such as polymethyl methacrylate (PMMA) with a primary amine. However, when the (meth) acrylic resin is imidized, Structure is known.

In order to produce a (meth) acrylic resin having a large content of glutarimide structure, it is important to efficiently produce an anhydroglutaric acid structure in a (meth) acrylic resin. It is known that the (meth) acrylic resin is subjected to anhydrous glutaric oxidation of a (meth) acrylic resin by using an extruder at a high temperature and under a reduced pressure condition for accelerating the reaction of anhydrous glutaric oxidation.

In the present invention, first, an anhydroglutaric acid resin is prepared from a (meth) acrylic resin by using an extruder or the like, and if necessary, the resulting anhydroglutaric acid resin is isolated, and the obtained anhydroglutaric acid resin is imidized , The glutarimide structure can be efficiently produced into (meth) acrylic. This method is effective when an aniline having a low basicity is used as an imidizing agent as compared with an alkylamine such as methylamine.

When preparing the anhydroglutaric acid resin from the (meth) acrylic resin, the catalyst can be used from the viewpoint of promoting the cyclization reaction to the anhydroglutaric acid structure.

As the catalyst for promoting the cyclization reaction to the anhydroglutaric acid structure, at least one member selected from the group consisting of an acid, a base and salts thereof can be used. The kind of the acid, the base and the salt thereof is not particularly limited. It is preferable that the catalyst is used within a range in which the transparency of the (meth) acrylic resin is not deteriorated without adversely affecting the color of the (meth) acrylic resin.

Examples of the acid include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid and methyl phosphate, but the present invention is not limited to these examples. Examples of the base include metal hydroxides, amines, imines, alkali metal derivatives, alkoxides, and ammonium hydroxide salts, but the present invention is not limited to these examples. Examples of salts of acids and bases include metal acetate, metal stearate and metal carbonate, but the present invention is not limited to these examples. Among these catalysts, a compound having an alkali metal is preferable because it exhibits an excellent reaction promoting effect with a small amount. Examples of the compound having an alkali metal include alkaline metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkaline metal hydroxides such as sodium methoxide, sodium ethoxide, sodium phenoxide, potassium methoxide, potassium ethoxide, potassium phenoxide and the like , Alkali metal alkoxide compounds of organic carboxylic acids such as lithium acetate, sodium acetate, potassium acetate, sodium stearate and the like, but the present invention is not limited to these examples. Of these compounds having an alkali metal, sodium hydroxide, sodium methoxide, lithium acetate and sodium acetate are preferable, and sodium methoxide and lithium acetate are more preferable.

The amount of the catalyst is not particularly limited, but is usually about 0.01 to 1 part by weight per 100 parts by weight of the (meth) acrylic resin.

Further, the (meth) acrylic resin may contain other thermoplastic resin within the range not hindering the object of the present invention. Examples of other thermoplastic resins include olefin-based polymers such as polyethylene, polypropylene, ethylene-propylene copolymer and poly (4-methyl-1-pentene); Halogen-containing polymers such as vinyl chloride and vinyl chloride resin; (Meth) acrylic polymers such as polymethyl methacrylate; Styrene-based polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene block copolymer; Polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; Biodegradable polyesters such as polylactic acid and polybutylene succinate; Polyamides such as nylon 6, nylon 66 and nylon 610; Polyacetal; Polycarbonate; Polyphenylene oxide; Polyphenylene sulfide; Polyether ether ketone; Polyether nitrile; Polysulfone; Polyethersulfone; Polyoxybenzylene; Polyamideimide; Polybutadiene rubber, rubber such as acrylic rubber, and the like, but the present invention is not limited to these examples.

The (meth) acrylic resin may contain, for example, an antioxidant such as a hindered phenol-based antioxidant, a phosphorus-based antioxidant, or a sulfur-based antioxidant within a range that does not hinder the object of the present invention; Stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; Reinforcing materials such as glass fiber and carbon fiber; Near infrared absorbers; Flame retarding agents such as tris (dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; An antistatic agent such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant; Coloring agents such as inorganic pigments, organic pigments and dyes; Fillers such as organic fillers and inorganic fillers; Resin modifiers; Plasticizers; Lubricants and the like may be contained.

The optical film of the present invention can be produced by a melt extrusion molding method such as a T-die method or an inflation method, a cast molding method, a press molding method or the like using a (meth) acrylic resin. When the optical film is produced by the melt extrusion method, for example, a single screw extruder, a twin screw extruder, or the like can be used.

As described above, the optical film of the present invention can be obtained. However, from the viewpoint of enhancing the mechanical strength, the optical film of the present invention is preferably uniaxially or biaxially stretched, more preferably biaxially stretched. Examples of the method for biaxially stretching the optical film of the present invention include a sequential biaxial stretching method and a simultaneous biaxial stretching method, but the present invention is not limited to these examples.

The stretching temperature at which the optical film of the present invention is stretched is preferably not more than 20 times the glass transition temperature of the (meth) acrylic resin from the standpoint of stretching the optical film without causing breakage in the optical film, More preferably from a temperature lower than the glass transition temperature of the (meth) acrylic resin by 10 占 폚 to a temperature higher than the glass transition temperature by 30 占 폚 to be.

The stretching magnification of the optical film is preferably 1.5 to 3 times, more preferably 1.5 to 2.5 times, from the viewpoint of increasing the mechanical strength in either the longitudinal direction or the transverse direction perpendicular to the longitudinal direction desirable.

The dimensional change ratio of the stretched optical film is preferably 1.0% or less, more preferably 0.7% or less, and still more preferably 0.5% or less, from the viewpoint of improving the durability of the film subjected to the secondary processing such as ITO % Or less, and still more preferably 0.2% or less.

Since the thickness of the optical film of the present invention differs depending on its use or the like, it can not be uniformly determined. For example, when the optical film of the present invention is used for a protective film, an antireflection film, a polarizing film, and the like used in an image display device such as a liquid crystal display device or an organic EL display device, the thickness of the optical film is preferably Is preferably 1 to 250 占 퐉, more preferably 10 to 100 占 퐉, and still more preferably 20 to 80 占 퐉. When the optical film of the present invention is used for a transparent conductive film used for an ITO deposited film, a silver nanowire film, a metal mesh film, or the like, the thickness of the optical film is preferably 20 to 400 μm, More preferably from 30 to 350 占 퐉, and still more preferably from 40 to 300 占 퐉.

In the present specification, the thickness of the optical film is a thickness measured by using, for example, a decimation micrometer (manufactured by Mitsuto Corporation).

The in-plane retardation (Re) of the optical film of the present invention is preferably 20 nm or less, more preferably 10 nm or less, further preferably 5 nm or less from the viewpoint of suppressing the anisotropy of the refractive index of the optical film and decreasing birefringence , And still more preferably 3 nm or less. The absolute value of the thickness direction retardation (Rth) of the optical film of the present invention is preferably 20 nm or less from the viewpoint of suppressing the anisotropy of the refractive index of the optical film and decreasing the birefringence, similarly to the in-plane retardation (Re) Is preferably 10 nm or less, more preferably 5 nm or less, and still more preferably 3 nm or less.

In this specification, the in-plane retardation (Re) and the thickness direction retardation (Rth) of the optical film with respect to light having a wavelength of 590 nm were measured using a retardation film / optical material inspection apparatus (Otsuka Denshi Co., Is used and the value is measured under the condition of an incident angle of 40 °.

The in-plane retardation (Re) of the optical film is represented by the formula:

[In-plane retardation (Re)] = (nx-ny) xd

Wherein nx is a refractive index in the slow axis direction (direction indicating the maximum refractive index in the plane of the optical film) with respect to light having a wavelength of 590 nm, and ny is a refractive index in the fast axis direction (perpendicular to nx in the plane of the optical film Ny represents the refractive index in the fast axis direction in the plane of the film, and d represents the thickness (nm) of the optical film)

. ≪ / RTI >

Further, the thickness direction retardation (Rth)

(Thickness direction retardation (Rth)) = {(nx + ny) / 2-nz} xd

(Where nx is refractive index in the slow axis direction with respect to light having a wavelength of 590 nm, ny is refractive index in the fast axis direction, nz is refractive index in the thickness direction of the film, and d is the thickness (nm)

. ≪ / RTI >

The absolute value of the photoelastic coefficient of the optical film of the present invention with respect to light having a wavelength of 590 nm is preferably 10 x 10 < ^-12 > Pa < ^-1 > or less from the viewpoint of suppressing light leakage, particularly light leakage under high- And more preferably not more than 6 × 10 ^-12 Pa ^-1 .

In the present specification, the photoelastic coefficient of the optical film with respect to the light having a wavelength of 590 nm is obtained by cutting the sample into 20 mm x 50 mm with the elongation direction of the optical film as the long side to prepare a sample, and this sample is measured with an ellipsometer ), A birefringence was measured at three points while a stress load of 5 to 25 N was applied in parallel with the stretching direction, and birefringence for stress was measured using light having a wavelength of 590 nm Is a value obtained by obtaining the slope of the photoelastic coefficient.

The coefficient of linear expansion of the optical film of the present invention in the temperature range of 60 to 100 占 폚 is preferably 80 占^{10-6K- 1} or less, more preferably 70 占 폚 or less from the viewpoint of suppressing the dimensional change under high- 10 ^-6 K ^-1 or less.

In the present specification, the coefficient of linear expansion of the optical film at 60 to 100 ° C was measured at 60 ° C under the following measurement conditions using a thermomechanical measuring device (Shimadzu Corporation, product number: TMA-60) And found as a warp at 100 deg.

〔Measuring conditions〕

Sample size: 5 mm x 20 mm (with the elongation direction being the long side)

Pretreatment of samples: Pretreatment was carried out at 60 ° C for 15 hours and then cooled to room temperature

· Weight measurement: 5g

Heating rate: 5 ° C / min

The absorptivity of the optical film of the present invention is preferably 3.0% or less, more preferably 2.5% or less, furthermore preferably 2.0% or less, from the viewpoint of improving the moldability of the ITO film. The absorption rate of the optical film is a value measured based on the method described in the following examples.

A coating layer may be formed on the surface of the optical film of the present invention as necessary. Examples of the coating layer include an antistatic layer, a pressure sensitive adhesive layer, an adhesive layer, an adhesive layer, an antiglare layer, a photocatalytic layer, an antifouling layer, an antireflection layer, a hard coat layer, an ultraviolet ray shielding layer, a heat ray shielding layer, A gas barrier layer, and the like. However, the present invention is not limited to these examples.

As described above, the optical film of the present invention has a weak positive birefringence based on the repeating unit represented by the formula (I) and has a weak birefringence based on the repeating unit represented by the formula (II). However, Since birefringence is negated, it has a low birefringence as a whole. Further, since the optical film of the present invention has a repeating unit represented by the formula (I), it is excellent in heat resistance, and when it has substantially no repeating unit based on an aromatic vinyl monomer represented by styrene, And has an excellent property of having a hard surface hardness and a low photoelastic coefficient which are characteristics based on repeating units.

The optical film of the present invention can be used as a polarizer protective film, a retardation film, a viewing angle compensation film, a light diffusion film, a reflection film, an anti-reflection film, It is expected to be used in applications such as an antiglare film, a luminance improvement film, a conductive film for a touch panel, a diffusion plate, a light guide, and a prism sheet. Therefore, the optical film of the present invention is expected to be suitably used for, for example, an image display device such as a liquid crystal display device, a capacitive touch panel, and the like.

Further, a transparent conductive layer, an optical adjustment layer, a transparent hard coat layer, an antiglare layer, an antireflection layer, and the like may be formed on at least one surface of the optical film of the present invention.

The optical film in which the transparent conductive layer is formed on at least one surface of the optical film of the present invention can be used as the transparent conductive film. As the transparent conductive layer, for example, an inorganic compound layer having a property of reflecting infrared rays such as an indium-tin oxide (ITO) layer, a metal mesh layer made of silver, copper, nickel, tungsten, The present invention is not limited to these examples.

When the transparent conductive layer is an inorganic compound layer, the thickness of the transparent conductive layer is preferably 0.001 to 10 占 퐉, more preferably 0.005 to 1 占 퐉, and still more preferably 0.01 to 0.5 占 퐉, from the viewpoint of improving conductivity and light transmittance to be. When the transparent conductive layer is a metal mesh layer, the thickness of the transparent conductive layer is preferably 0.1 to 30 占 퐉, more preferably 0.1 to 10 占 퐉, still more preferably 1 to 10 占 퐉, from the viewpoint of improving conductivity and light transmittance, 5 mu m.

The optical adjustment layer is a layer for appropriately adjusting the transmittance or reflectance of the incident light beam. The optical adjustment layer can be formed by alternately laminating a low refractive index layer having a relatively low refractive index and a high refractive index layer having a relatively high refractive index, for example, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-201450.

Example

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1

(A) Preparation of (meth) acrylic resin

29.5 parts by weight of aniline, and 33.2 parts by weight of toluene were added to a 2 liter autoclave, to which methyl methacrylate (SUMIFEX EX, trade name: SumiPEX EX, weight average molecular weight: 140,000) The autoclave was heated to 240 캜 and stirred for 3 hours to obtain a reaction solution.

Subsequently, the reaction solution obtained above was passed through a vent type screw twin-screw extruder having a barrel temperature of 260 DEG C, a revolution of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), a number of rear vents of 1, : 15 mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and devolatilization was carried out in this extruder and extrusion was carried out to obtain pellets of a transparent (meth) acrylic resin. The weight average molecular weight of the (meth) acrylic resin obtained above was 100,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having repeating units wherein R ⁵ is a methyl group, R ⁶ is a methyl group, and a glass transition temperature is 142 ° C. The imidization ratio of the (meth) acrylic resin, the content ratio of the repeating unit represented by the formula (II) and the stress optical coefficient (Cr) were investigated based on the following methods. As a result, the imidization ratio of the (meth) acrylic resin was 9.6%, the content of the repeating unit represented by the formula (II) was 82.1% by weight and the stress optical coefficient (Cr) was -0.01 × 10 ^-9 Pa ^-1 .

Also in the following Examples and Comparative Examples, the imidization ratio of the (meth) acrylic resin, the content ratio of the repeating unit represented by the formula (II) and the stress optical coefficient (Cr) were investigated based on the following methods.

[Imidization Rate]

(Meth) imidization ratio of the acrylic resin has an imide group of absorption and, 1680㎝ ^-1 vicinity derived from ester carbonyl absorption and, near 1720㎝ ^-1 derived from carboxylic acid anhydride group in the vicinity 1803㎝ ^-1 The imidization ratio was determined from the intensity ratio of absorption derived from the above. Here, the imidization ratio is the ratio of the imidocarbonyl group in the total carbonyl group.

[Content Ratio of Repeating Unit Represented by Formula (II)] [

The content of the repeating unit represented by the formula (II) in the (meth) acrylic resin was determined by measuring the ¹ H-NMR spectrum using an NMR measuring device (Unity Plus 400, manufactured by Varian).

More specifically, by dissolving 1,1,2,2-tetrachloroethane (molecular weight: 167.85, weight: b) as the internal standard and a (meth) acrylic resin (weight: 2 proton minutes) and the ratio (peak area of the peak area B which is derived from the peak area a and naepyo proton derived from the R ⁶ proton adjacent to the area ratio [ester group of a peak derived from the R ⁶ proton adjacent to the ester carbonyl group a / Peak area B)], the content ratio of the repeating unit represented by the formula (II) was calculated.

For example, when R ⁴ in the repeating unit represented by the formula (II) is a hydrogen atom, R ⁵ is a methyl group, and R ⁶ is a methyl group (the molecular weight of the repeating unit is 100.12) The content (% by weight) of the unit is expressed by the formula:

[Content ratio (% by weight) of the repeating unit represented by the formula (II)]]

= [(Peak area A / peak area B) (2/3) x (b / 167.85) x (1/100.12)] x (100 / a)

. ≪ / RTI >

[Stress optical coefficient (Cr)]

(Cr) of the (meth) acrylic resin was cut into a rectangular shape of 60 mm x 20 mm, and a weight was selected so as to have a stress of 1 N / mm 2 or less and attached to the lower end of the unstretched film.

The unstretched film was set at a chuck distance of 40 mm at a temperature of 3 ° C higher than the glass transition temperature of the (meth) acrylic resin to a constant-temperature drier (manufactured by Ajuzon Co., Ltd., product number: DOV-450A) After the stretching was carried out, the heating was stopped, and the sample was cooled at a cooling rate of about 1 占 폚 / min until the temperature became 40 占 폚 lower than the glass transition temperature of the (meth) acrylic resin. Then, the obtained stretched film was taken out from the constant temperature dryer, and the length, thickness and weight of the stretched film were measured, and the in-plane retardation (Re) of the stretched film was measured.

The length, thickness and weight of the stretched film were measured in the same manner as above using the weight of four kinds of mass so that the stress was 1 N / mm 2 or less, and the in-plane retardation (Re) of the stretched film was measured .

Based on the above results, the stress optical coefficient (Cr) was calculated based on the measurement method described in Polymer Society, "Frontier of transparent plastic (polymer frontier 21 series)", NTS, October 2006, did. More specifically,? N (nx-ny) is plotted on the y-axis and? Is plotted on the X-axis to determine the slope of the straight line obtained by the least squares method and the value of the slope is used as the stress optical coefficient (Cr). Nx is the refractive index in the slow axis direction (the direction showing the maximum refractive index in the film plane) in the plane of the film, and ny is the refractive index in the fast axis direction (direction perpendicular to nx in the film plane) And? Is a stress (N / m 2) for stretching.

(B) Production of optical film

The pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), melt extruded from a coat hanger type T die (width 150 mm) And discharged on a cooling roll at 140 DEG C to prepare an unoriented film having a thickness of 160 mu m.

Subsequently, the obtained unoriented film was cut into 96 mm x 96 mm and extruded at a rate of 240 mm / min at a temperature of 157 DEG C using a sequential biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., part no: X-6S) (MD direction) and transverse direction (TD direction) at a stretching speed of 1 mm / sec.

The stretched film obtained above was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

The haze, total light transmittance, the number of times of the theft test in the MIT, the film impact strength, and the pencil hardness were examined as physical properties of the optical film obtained as described above according to the following methods. The results are shown in Table 1. Table 1 also shows the glass transition temperature of the (meth) acrylic resin as an index of heat resistance.

(1) Haze and total light transmittance

The haze and the total light transmittance were measured using a turbidity meter (manufactured by Nippon Denshoku Chemical Co., Ltd., product number: NDH 5000).

(2) Number of thefts in MIT

The number of times of the theft test in the MIT was cut according to JIS P8115 by cutting the optical film to a length of 15 mm and a length of 90 mm and the obtained test piece was subjected to a tearing test by an aberrant tester (product of Tester San-kyo Co., Ltd., product number: BE-201) And a load of 200 g in an atmosphere of a temperature of 23 캜 and a relative humidity of 50%.

(3) Film impact strength

The film impact strength was measured in accordance with ASTM D3420 in an atmosphere of a temperature of 23 DEG C and a relative humidity of 50% using a film impact tester (manufactured by TESTER SANKYO CO., LTD., Product number: BU-302)

(4) Pencil Hardness

, A pencil scratch hardness tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) was used in accordance with JIS K5600-5-4 (1999), and a load of 750 g was measured.

Example 2

(A) Preparation of (meth) acrylic resin

A (meth) acrylic resin was obtained in the same manner as in Example 1 except that the reaction temperature of the autoclave was changed to 245 캜. The weight average molecular weight of the obtained (meth) acrylic resin was 100,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ in the formula (II) ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 152 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization ratio of the (meth) acrylic resin was 20.9%, the content of the repeating unit represented by the formula (II) was 60.4% by weight, and the stress optical coefficient (Cr) was 0.02 10 ^-9 Pa ^-1 .

(B) Production of optical film

Except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1 and the T die temperature was changed to 280 占 폚, the roll temperature was set to 150 占 폚, and the stretching temperature was changed to 167 占 폚, An optical film having a thickness of 40 탆 was obtained in the same manner as in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Example 3

(A) Preparation of (meth) acrylic resin

A (meth) acrylic resin was obtained in the same manner as in Example 1 except that the reaction temperature of the autoclave was changed to 247 占 폚 and the barrel temperature was changed to 270 占 폚. The weight average molecular weight of the obtained (meth) acrylic resin was 90,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 160 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization ratio of the (meth) acrylic resin was 23.9%, the content of the repeating unit represented by the formula (II) was 55.6 wt%, and the stress optical coefficient (Cr) was 0.04 x 10 ^-9 Pa ^-1 .

(B) Production of optical film

Except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1 and the T-die temperature was changed to 285 캜, the roll temperature was set to 155 캜, and the stretching temperature was changed to 175 캜. An optical film having a thickness of 40 탆 was obtained in the same manner as in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Example 4

(A) Preparation of (meth) acrylic resin

A (meth) acrylic resin was obtained in the same manner as in Example 1 except that the reaction temperature of the autoclave was changed to 250 캜 and the barrel temperature was changed to 270 캜. The weight average molecular weight of the obtained (meth) acrylic resin was 90,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit wherein R ⁵ is a methyl group, R ⁶ is a methyl group, and a glass transition temperature is 167 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization rate of the (meth) acrylic resin was 30.9%, the content of the repeating unit represented by the formula (II) was 45.5% by weight, and the stress optical coefficient (Cr) was 0.05 10 ^-9 Pa ^-1 .

(B) Production of optical film

Except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1 and the T die temperature was changed to 295 占 폚, the roll temperature was set to 165 占 폚, and the stretching temperature was changed to 182 占 폚, An optical film having a thickness of 40 탆 was obtained in the same manner as in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Example 5

(A) Preparation of (meth) acrylic resin

100 parts by weight of the (meth) acrylic resin obtained in Example 1 was blended with 6,6 ', 6 "- (1,3,5-triazine-2,4,6-triyl) tris (3-hex Acrylate resin in a proportion of 0.66 part by weight of a polyoxyalkylene-polyoxyalkylene block copolymer (trade name: Adekastab (registered trademark) LA-F70, manufactured by ADEKA) The mixture was kneaded at 260 DEG C and extruded to obtain pellets of transparent (meth) acrylic resin. The weight average molecular weight of the obtained (meth) acrylic resin was 100,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having repeating units wherein R ⁵ is a methyl group, R ⁶ is a methyl group, and a glass transition temperature is 142 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization ratio of the (meth) acrylic resin was 9.6%, the content of the repeating unit represented by the formula (II) was 82.1% by weight, and the stress optical coefficient (Cr) was 0.03 10 ^-9 Pa ^-1 .

(B) Production of optical film

An optical film having a thickness of 40 占 퐉 was obtained in the same manner as in Example 1 except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Example 6

(A) Preparation of (meth) acrylic resin

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, 65.2 parts by weight of toluene as a polymerization solvent, and 16.3 parts by weight of methanol were mixed in a reaction part equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas introducing tube, , 0.05 part by weight of an antioxidant (trade name: Adekastab 2112, manufactured by ADEKA CORPORATION) and 0.2 part by weight of n-dodecylmercaptan as a chain transfer agent were charged and the temperature was raised to 80 캜 while nitrogen gas was passed through the reaction part. At the point of time when the reflux due to the elevated temperature was started, 0.10 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601 made by Wako Pure Chemical Industries, And 0.20 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was dropped into the reaction part over 2 hours, Solution polymerization was carried out under reflux at 80 to 85 캜, and aging was carried out for 4 hours after completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate). The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the obtained polymer solution was 21.2% by weight. The weight average molecular weight of the (meth) acrylic resin was 100,000.

Next, 100 parts by weight of the polymer solution obtained above and 92.5 parts by weight of aniline were uniformly mixed, and the resulting mixture was extruded at a barrel temperature of 270 캜, a revolution of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) At a throughput rate of 300 g / h in terms of a resin amount in a vent-type screw twin-screw extruder (hole diameter: 15 mm, L / D: 45) having a number of pores of 2, and then subjected to devolatilization in the extruder, To obtain pellets of a (meth) acrylic resin. The weight average molecular weight of the obtained (meth) acrylic resin was 90,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 154 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization ratio of the (meth) acrylic resin was 23.1%, the content of the repeating unit represented by the formula (II) was 56.9 wt%, and the stress optical coefficient (Cr) was 0.04 x 10 ^-9 Pa ^-1 .

(B) Production of optical film

Except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1 and the T die temperature was changed to 285 deg. C, the roll temperature to 150 deg. C, and the stretching temperature to 169 deg. An optical film having a thickness of 40 탆 was obtained in the same manner as in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Example 7

(A) Preparation of (meth) acrylic resin

The polymer solution obtained in Example 6 was extruded through a vent type screw twin screw extruder having a barrel temperature of 260 DEG C, a rotation speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), a number of rear vents of 1, : 15 mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and subjected to devolatilization in the extruder to obtain pellets of a transparent (meth) acrylic resin. The weight average molecular weight of the obtained (meth) acrylic resin was 100,000, and the glass transition temperature was 136 占 폚.

The pellets thus obtained were extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 45) having a barrel temperature of 270 DEG C, a rotation speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) At a treatment rate of 300 g / h in terms of a resin amount, and aniline was injected from the back of the hopper by a liquid addition pump at a charging rate of 277 g / h and extruded to obtain pellets of a transparent (meth) acrylic resin. The weight average molecular weight of the obtained (meth) acrylic resin was 90,000.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 148 ° C. The imidization ratio of the (meth) acrylic resin, the content of the repeating unit represented by the formula (II), and the stress optical coefficient (Cr) were investigated in the same manner as in Example 1. As a result, the imidization ratio of the (meth) acrylic resin was 16.8%, the content of the repeating unit represented by the formula (II) was 67.4 wt%, and the stress optical coefficient (Cr) was 0.01 10 ^-9 Pa ^-1 .

(B) Production of optical film

Except that the (meth) acrylic resin obtained as described above was used as the (meth) acrylic resin in Example 1 and the T die temperature was changed to 275 deg. C, the roll temperature to 145 deg. C, and the stretching temperature to 163 deg. An optical film having a thickness of 40 탆 was obtained in the same manner as in Example 1.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1

(A) Preparation of (meth) acrylic resin

A 2-liter autoclave was charged with 16 parts by weight of a methyl methacrylate-styrene copolymer (trade name: Estyrene MS600, weight average molecular weight: 130,000, manufactured by Shin-Nittsu Sumikin Kakaku Co., Ltd.), 40% methylamine- And 24 parts by weight of toluene. The autoclave was heated to 230 ° C and stirred for 2 hours.

(B) Production of optical film

The reaction solution thus obtained was passed through a vent type screw twin-screw extruder (hole diameter: 15 mm) having a barrel temperature of 260 ° C, a rotational speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and subjected to devolatilization in the extruder to obtain pellets of transparent resin. The obtained methyl methacrylate-styrene imide resin had a glass transition temperature of 143 占 폚 and a weight average molecular weight of 90,000.

Next, the imidization ratio and the stress optical coefficient (Cr) of the methyl methacrylate-styrene-based imide resin obtained above were measured in the same manner as in Example 1. As a result, the imidization rate of the methyl methacrylate-styrene imide resin was 89.5% and the stress optical coefficient (Cr) was -1.72 10 ^-9 Pa ^-1 .

The styrene content in the methyl methacrylate-styrene-based imide resin obtained above was measured in accordance with the following method. As a result, the styrene content was 44.9% by weight.

[Method of measuring styrene content]

The styrene content of the resin was determined by measuring the ¹ H-NMR spectrum using an NMR measuring device (manufactured by Varian, product name: Unity Plus 400) and measuring the area of the hydrogen atoms derived from the aromatic rings of the long- Based on the area ratio of the derived hydrogen atoms.

(B) Production of optical film

In the same manner as in Example 1 except that the methyl methacrylate-styrene type imide resin obtained above was used in place of the (meth) acrylic resin in Example 1 and the stretching temperature was changed to 158 캜, Was obtained.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2

(A) Preparation of (meth) acrylic resin

In Comparative Example 1, the methyl methacrylate-styrene copolymer was changed to a methyl methacrylate-styrene copolymer (Trade name: Estyrene MS700, weight average molecular weight: 130,000, manufactured by Shin-Nittsu Sumikin Kagaku Co., Ltd.) , And the amount of the 40% methylamine-methanol solution was changed to 3.5 parts by weight, a methyl methacrylate-styrene type imide resin was obtained in the same manner as in Comparative Example 1. The weight average molecular weight of the obtained methyl methacrylate-styrene imide resin was 90,000, and the glass transition temperature was 152 占 폚. Also, the methyl methacrylate-styrene imidization ratio was 90.8% of the imide resin, stress optical system be (Cr) was 0.09 × 10 ^-9 ㎩ ^-1.

The styrene content in the methyl methacrylate-styrene-based imide resin obtained above was measured in the same manner as in Comparative Example 1, and as a result, the styrene content was 34.4% by weight.

(B) Production of optical film

In the same manner as in Comparative Example 1 except that the methyl methacrylate-styrene type imide resin obtained above was used as the methyl methacrylate-styrene type imide resin and the T die temperature was set to 280 ° C and the roll temperature was set to 150 ° C, An optical film having a thickness of 40 占 퐉 was obtained in the same manner as in Comparative Example 1 except that the temperature was changed to 167 占 폚.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3

(A) Preparation of (meth) acrylic resin

In Comparative Example 1, the methyl methacrylate-styrene copolymer was changed to a methyl methacrylate-styrene copolymer (trade name: Estyrene MS800, weight average molecular weight: 130,000, manufactured by Shin-Nittsu Sumikin Kagaku Co., Ltd.) , And the amount of the 40% methylamine-methanol solution was changed to 4 parts by weight, a methyl methacrylate-styrene type imide resin was obtained in the same manner as in Comparative Example 1. The weight average molecular weight of the obtained methyl methacrylate-styrene imide resin was 90,000, and the glass transition temperature was 160 占 폚. Also, the methyl methacrylate-styrene imidization ratio was 92.6% of the imide resin, stress optical system be (Cr) was 0.93 × 10 ^-9 ㎩ ^-1.

The styrene content in the methyl methacrylate-styrene copolymer obtained above was measured in the same manner as in Comparative Example 1. As a result, the styrene content was 23.5% by weight.

(B) Production of optical film

In the same manner as in Comparative Example 1 except that the methyl methacrylate-styrene type imide resin obtained as described above was used as the methyl methacrylate-styrene type imide resin and the T die temperature was set to 285 캜 and the roll temperature was set to 155 캜, An optical film having a thickness of 40 占 퐉 was obtained in the same manner as in Comparative Example 1 except that the temperature was changed to 175 占 폚.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical film obtained above were examined. The results are shown in Table 1.

In addition, the physical properties of the optical film obtained above were examined in the same manner as in Example 1. The results are shown in Table 1.

From the results shown in Table 1, all of the optical films obtained in the Examples had low birefringence because they had good heat resistance, haze, total light transmittance, modulus in the MIT and impact strength, The pencil hardness is high, and the absolute value of the photoelastic coefficient is small.

Production Example 1

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aged for 4 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.1 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in the cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, Solution.

The polymerization solution thus obtained was passed through a vent type screw twin-screw extruder (hole diameter: 15 mm) having a barrel temperature of 290 ° C, a revolution of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and devolatilization was carried out in this biaxial extruder and extrusion was carried out for about 0.9 minutes in the axial retention time to obtain pellets of transparent (meth) .

The (meth) acrylic resin thus obtained had a weight average molecular weight of 100,000 and a glass transition temperature of 131 占 폚. The anhydrous glutaric anhydride ratio of the (meth) acrylic resin obtained above was examined based on the following method. As a result, the resulting (meth) acrylic resin had an anhydroglutar oxidation rate of 17.5%.

Also in the following Examples and Comparative Examples, the anhydrous glutar oxidation rate of the (meth) acrylic resin was examined based on the following method.

[Anhydrous Glutar Oxidation Rate]

(Meth) acrylic resin in the anhydrous glue tar oxidation rate is 1803㎝ ^-1 vicinity of the carboxylic acid and the absorption derived from anhydride groups, and 1720㎝ absorption derived from the ester carbonyl group in the vicinity of ^-1, imide vicinity of 1680㎝ ^-1 The anhydrous glutar oxidation rate was determined from the intensity ratio of absorption derived from the carbonyl group. Here, the anhydrous glutar oxidation rate is the ratio of the carboxylic acid anhydride group in the total carbonyl group.

Example 8

The pellets obtained in Production Example 1 were extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 1 mm) having a barrel temperature of 290 DEG C, a revolution of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 420 g / h in terms of a resin amount, and aniline was injected from the back of the hopper at a charging rate of 101 g / h by means of a liquid addition pump and extruded at an in- Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 90,000. The (meth) acrylic resin is a R ¹ is a methyl group in the formula (I), R ² is a hydrogen atom, and R ³ is R ⁴ is a hydrogen atom in the repeating unit and the formula (Ⅱ) phenyl group, R ⁵ is (Meth) acrylic resin having a repeating unit in which R ⁶ is a methyl group and having a glass transition temperature of 162 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 44.1%, the content of the repeating unit represented by the formula (II) was 37.3% by weight, and the stress optical coefficient (Cr) was 0.08 10 ^-9 Pa ^-1 . The content of the metal in the (meth) acrylic resin was examined based on the following method. As a result, the content of the metal in the obtained (meth) acrylic resin was 470 ppm.

Also in the following Examples and Comparative Examples, the content of the metal in the (meth) acrylic resin was examined based on the following method.

[Content of metal in (meth) acrylic resin]

The content of the metal in the (meth) acrylic resin is measured by using an ICP emission spectrometer [(meth) acrylic resin] using a solution obtained by carbonizing a (meth) acrylic resin with a microwave sample preprocessing apparatus (manufactured by Milestone General Corporation, trade name: ETHOS One) (Trade name: CIROS-120 manufactured by Rigaku Corporation).

Production Example 2

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aged for 4 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.05 weight part of sodium methoxide as a catalyst (cyclization catalyst) for cyclization condensation reaction into 5.0 weight part of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 占 폚 for 20 minutes, Solution.

The polymerization solution thus obtained was passed through a vent type screw twin-screw extruder (hole diameter: 15 mm) having a barrel temperature of 280 ° C, a rotation speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 420 g / h in terms of a resin amount, and devolatilization was carried out in this twin screw extruder and extrusion was carried out for about 3.2 minutes in the axial retention time to obtain pellets of a transparent (meth) .

The (meth) acrylic resin thus obtained had a weight average molecular weight of 9.7 million and a glass transition temperature of 131 占 폚. In addition, the (meth) acrylic resin had an anhydroglutaric anhydride oxidation rate of 16.3%.

Example 9

The pellets obtained in Preparation Example 2 were extruded through a vent type screw twin-screw extruder (hole diameter: 15 mm, L / D: 1 mm) having a barrel temperature of 290 DEG C, a rotation speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 420 g / h in terms of a resin amount, and aniline was injected from the back of the hopper into the liquid addition pump at an injection rate of 101 g / h, and extruded at an intrinsic retention time of about 5.2 minutes, Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 8.9 million. The (meth) acrylic resin is a R ¹ is a methyl group in the formula (I), R ² is a hydrogen atom, and R ³ is R ⁴ is a hydrogen atom in the repeating unit and the formula (Ⅱ) phenyl group, R ⁵ is (Meth) acrylic resin having a repeating unit in which R ⁶ is a methyl group and having a glass transition temperature of 167 ° C.

The imidization ratio of the (meth) acrylic resin obtained above was 47.2%, the content of the repeating unit represented by the formula (II) was 35.4% by weight, and the stress optical coefficient (Cr) was 0.11 10 ^-9 Pa ^-1 . The content of the metal in the (meth) acrylic resin was 235 ppm.

Production Example 3

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) Further, aging was carried out over 4 hours to obtain a polymer solution.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.12 parts by weight of lithium acetate, which is a catalyst for cyclization condensation (cyclization catalyst), in 11.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes to prepare a homogeneous polymerization solution did.

The polymerization solution thus obtained was passed through a vent type screw twin-screw extruder (hole diameter: 15 mm) having a barrel temperature of 290 ° C, a revolution of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and subjected to devolatilization in the extruder and extruded at an extrusion temperature of about 3.0 minutes to obtain pellets of a transparent (meth) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 100,000 and the glass transition temperature was 130 占 폚. The (meth) acrylic resin had anhydrous glutar oxidation rate of 15.9%.

Example 10

The pellets obtained in Preparative Example 3 were extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 20 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a treatment rate of 432 g / h in terms of the resin amount, and aniline was injected from the back of the hopper at a charging rate of 104 g / h by a liquid addition pump and extruded at an in- Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 9.2 million. The (meth) acrylic resin is a R ¹ is a methyl group in the formula (I), R ² is a hydrogen atom, and R ³ is R ⁴ is a hydrogen atom in the repeating unit and the formula (Ⅱ) phenyl group, R ⁵ is (Meth) acrylic resin having a repeating unit in which R ⁶ is a methyl group and having a glass transition temperature of 161 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 42.0%, the content ratio of the repeating unit represented by the formula (II) was 38.5% by weight, and the stress optical coefficient (Cr) was 0.07 10 ^-9 Pa ^-1 . The content of the metal in the (meth) acrylic resin was 135 ppm.

Except that the pellets obtained in Examples 8 to 10 were used and the T-die temperature, the roll temperature and the stretching temperature in Example 1 were changed as shown in Table 2. In the same manner as in Example 1, ≪ / RTI >

Then, the in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical films obtained in Examples 8 to 10 were examined. The results are shown in Table 3. The physical properties of these optical films were investigated in the same manner as in Example 1. The results are given in Table 3.

From the results shown in Table 3, all of the optical films obtained in the Examples had low birefringence because they had good heat resistance, haze, total light transmittance, modulus and impact strength in MIT, The pencil hardness is high, and the absolute value of the photoelastic coefficient is small.

Production Example 4

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) Further, aging was carried out over 4 hours to obtain a polymer solution.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.1 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in the cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, .

The polymerization solution thus obtained was passed through a vent type screw twin screw extruder (hole diameter: 15 mm) having a barrel temperature of 290 ° C, a revolution of 238 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 300 g / h in terms of a resin amount, and subjected to devolatilization in this extruder and extruded at a retention time of about 0.9 minutes in the axial direction to obtain pellets of a transparent (meth) acrylic resin.

The (meth) acrylic resin thus obtained had a weight average molecular weight of 100,000 and a glass transition temperature of 131 占 폚.

Subsequently, the pellet obtained above was extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 420 g / h in terms of a resin amount, and aniline was injected from the back of the hopper at a charging rate of 162 g / h by means of a liquid addition pump and extruded at an intrinsic retention time of 5.6 minutes to obtain a transparent Meta) acrylic resin. The weight average molecular weight of the (meth) acrylic resin obtained above was 9.4 million.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 161 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 44.1%, the content of the repeating unit represented by the formula (II) was 37.3% by weight, and the stress optical coefficient (Cr) was 0.12 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 1.27 mmol / g.

In the following Production Examples and Examples, the acid value of the (meth) acrylic resin was examined based on the following method.

[Method for measuring the amount (acid value) of the acid component remaining in the (meth) acrylic resin]

To a solution obtained by dissolving 0.15 g of a (meth) acrylic resin in 24.94 g of methylene chloride, 14.85 g of methanol was added and stirred for 3 hours. Then, 2 drops of a 1 wt% phenolphthalein ethanol solution was added to this solution, and a 0.1N sodium hydroxide aqueous solution was added with stirring, and the stirring was continued at room temperature for 1 hour to obtain an aqueous 0.1N sodium hydroxide solution. 0.1 N hydrochloric acid was added dropwise to this solution, and a drop amount (B ml) of 0.1 N hydrochloric acid until the red color of the solution disappeared was measured.

Subsequently, 2 drops of a 1 wt% phenolphthalein ethanol solution was added to a mixture of 24.94 g of methylene chloride and 14.85 g of methanol, and a 0.1N sodium hydroxide aqueous solution was added with stirring, followed by stirring at room temperature for 1 hour to obtain a 0.1N aqueous sodium hydroxide solution Lt; / RTI > 0.1 N hydrochloric acid was added dropwise to this solution, and a drop amount (D ml) of 0.1 N hydrochloric acid required until the red color of the solution disappeared was measured.

(The total amount of carboxyl group and acid anhydride group) (m mol / g) remaining in the (meth) acrylic resin is represented by the formula:

(Amount of the acid component remaining in the (meth) acrylic resin (total amount of carboxyl group and acid anhydride group) (m mol / g)]

= 0.1 x [(A-B) - (C-D)] / 0.15

.

Example 11

The pellets obtained in Production Example 4 were extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 1 mm) having a barrel temperature of 260 캜, a revolution of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) (DBC) and 2.0 parts by weight of diazabicyclo-decene (DBU) were added to the raw material resin from the back of the hopper at a treatment rate of 420 g / And pellets of transparent (meth) acrylic resin were obtained by extrusion at an extrusion temperature of 5.2 minutes.

The weight average molecular weight of the (meth) acrylic resin obtained above was 80,000. The (meth) acrylic resin is a R ¹ is a methyl group in the formula (I), R ² is a hydrogen atom, and R ³ is R ⁴ is a hydrogen atom in the repeating unit and the formula (Ⅱ) phenyl group, R ⁵ is (Meth) acrylic resin having a repeating unit in which R ⁶ is a methyl group and having a glass transition temperature of 148 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 47.9%, the content of the repeating unit represented by the formula (II) was 59.1 wt%, and the stress optical coefficient (Cr) was -0.18 x 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 0.13 mmol / g.

Subsequently, the pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), the T die temperature was adjusted to 275 deg. C and melt extrusion was carried out from a coat hanger type T die And discharged on a cooling roll at a roll temperature of 145 DEG C to prepare an unoriented film having a thickness of 160 mu m.

The unstretched film obtained above was cut into 96 mm x 96 mm and extruded at a rate of 240 mm / min at a temperature of 168 DEG C using a sequential biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., part number: X-6S) (MD direction) and the transverse direction (TD direction) at a stretching speed of 2 mm in the drawing. After the unstretched film was subjected to biaxial stretching, the obtained stretched film was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆. The in-plane retardation and thickness retardation of the obtained optical film were 4.5 nm and -13.3 nm, respectively.

Subsequently, the absorptivity of the unstretched film and the retardation change value and the dimensional change rate in the thickness direction of the optical film obtained above were examined. The results are shown in Table 4.

The measurement method of the water absorption rate and the dimensional change rate is as follows. In the following Examples and Comparative Examples, the water absorption rate and the dimensional change rate were also examined based on the following methods.

[Absorption Rate]

The resin pellets were melt-press molded at a temperature of 250 DEG C at a pressure of 20 MPa for 2 minutes using a manual heating press machine (IMC-180C type, manufactured by Imoto Seisakusho Co., Ltd.) to obtain an unstretched film . The obtained unstretched film was dried at 80 DEG C for 24 hours, and its mass (X) was measured.

Then, the unstretched film obtained above was stored in a thermostatic chamber at 85 캜 and a relative humidity of 85%, and water was withdrawn after 250 hours from the thermostatic chamber to measure the mass (Y) of the unstretched film after water supply.

The water absorption of the unstretched film is expressed by the formula:

[Absorption ratio (%)] = [(Y-X) / X] 100

.

[Dimensional change rate]

The optical film was cut to produce three samples of a square sample having a length of 40 mm and a width of 40 mm. The lengths (La1, La2, La3, and La4) of the four sides of the sample were measured by Digital Nozzle.

Then, the sample was stored in a thermostatic chamber at 85 DEG C and 85% relative humidity, and after 250 hours had elapsed from the thermostatic chamber, the lengths (Lb1, Lb2, Lb3, Lb4) of four sides of the sample were measured again.

Next, the dimensional change rate on each side of the three samples was expressed by the formula:

[Dimensional change ratio (%)] = | (Lb-La) / La | x 100

(Where La is the length of one side before the test and Lb is the length of one side after the test)

The average value of the dimensional change rates of the three sides of the obtained three samples was obtained and the sum of the average values of the respective sides was obtained and then the sum was divided by four to obtain the dimensional change rate of the optical film.

Production Example 5

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aged for 4 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.02 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in a cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, .

The polymerization solution thus obtained was passed through a vent type screw twin screw extruder (hole diameter: 15 mm) having a barrel temperature of 290 ° C, a revolution of 238 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) Mm, L / D: 45) at a treatment rate of 480 g / h in terms of a resin amount, and devolatilization was carried out in this extruder and extrusion was carried out for about 3.7 minutes in the axial retention time to obtain pellets of a transparent (meth) acrylic resin.

The (meth) acrylic resin thus obtained had a weight average molecular weight of 10.2 million and a glass transition temperature of 130 ° C.

Subsequently, the pellet obtained above was extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a treatment rate of 432 g / h in terms of a resin amount, and aniline was injected from the back of the hopper at a charging rate of 250 g / h by means of a liquid addition pump and extruded at an axial retention time of 5.5 minutes, Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 9.7 million. The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 171 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 52.6%, the content of the repeating unit represented by the formula (II) was 29.5% by weight and the stress optical coefficient (Cr) was 0.23 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 1.58 mmol / g.

Example 12

The pellets obtained in Preparation Example 5 were extruded through a vent type screw twin-screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 260 DEG C, a rotation speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) (DBC) and 2.0 parts by weight of diazabicyclo-decene (DBU) were added to the raw material resin from the back of the hopper at a treatment rate of 420 g / And pellets of transparent (meth) acrylic resin were obtained by extrusion at an extrusion temperature of 5.2 minutes. The weight average molecular weight of the (meth) acrylic resin obtained above was 8.6 million.

The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 155 ° C.

The imidization ratio of the (meth) acrylic resin obtained above was 50.1%, the content of the repeating unit represented by the formula (II) was 44.2% by weight, and the stress optical coefficient (Cr) was -0.05 × 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 0.77 mmol / g.

Subsequently, the pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), the T die temperature was adjusted to 280 deg. C and melt extrusion was carried out from a coat hanger type T die (width 150 mm) And discharged onto a cooling roll at a roll temperature of 150 DEG C to prepare an unoriented film having a thickness of 160 mu m.

Subsequently, the unstretched film obtained above was cut to a size of 96 mm x 96 mm, and extruded at a temperature of 175 DEG C at 240 DEG C using a sequential biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., product number: X-6S) biaxial stretching was carried out in such a manner that the stretching ratio was doubled in the longitudinal direction (MD direction) and the transverse direction (TD direction) at the stretching speed of 1 / min. The stretched film obtained above was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆.

The in-plane retardation and thickness retardation of the optical film obtained above were 0.4 nm and -2.7 nm, respectively.

Subsequently, the absorptivity of the unstretched film and the retardation change value and the dimensional change rate in the thickness direction of the optical film obtained above were examined. The results are shown in Table 4.

Production Example 6

79.4 parts by weight of methyl methacrylate, 20.6 parts by weight of methacrylic acid, a mixed solvent of 90.0 parts by weight of toluene and 22.5 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aged for 4 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 20.6% by weight. The weight average molecular weight of the (meth) acrylic resin was 110,000.

Subsequently, a solution prepared by dissolving 0.05 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in a cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, .

Subsequently, the polymerization solution obtained above was passed through a vent type screw twin-screw extruder having a barrel temperature of 280 DEG C, a revolution of 238 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), a number of rear vents of 1, : 15 mm, L / D: 45) at a treatment rate of 624 g / h in terms of a resin amount, and devolatilization was carried out in this extruder and extrusion was carried out for about 2.6 minutes in the axial retention time to obtain pellets of a transparent (meth) .

The (meth) acrylic resin thus obtained had a weight average molecular weight of 9.8 million and a glass transition temperature of 130 占 폚.

Subsequently, the pellet obtained above was extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 420 g / h in terms of a resin amount, and aniline was injected from the back of the hopper by a liquid addition pump at a feed rate of 202 g / h and extruded to about 5.5 minutes in the axial direction, Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 9.2 million. The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 178 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 54.6%, the content of the repeating unit represented by the formula (II) was 26.2% by weight, and the stress optical coefficient (Cr) was 0.20 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 1.40 mmol / g.

Example 13

The pellets obtained in Preparative Example 6 were extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) (DBC) and 2.0 parts by weight of diazabicyclo-decene (DBU) were added to the raw material resin from the back of the hopper at a treatment rate of 420 g / And pellets of transparent (meth) acrylic resin were obtained by extrusion at an extrusion temperature of 5.2 minutes.

The weight average molecular weight of the (meth) acrylic resin obtained above was 8.3 million. The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group, R ⁶ is a methyl group, and has a glass transition temperature of 158 ° C.

The imidization rate of the (meth) acrylic resin obtained above was 52.2%, the content of the repeating unit represented by the formula (II) was 43.5% by weight, and the stress optical coefficient (Cr) was -0.12 × 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 0.48 mmol / g.

Then, the pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), melt extruded from a coat hanger type T die (width 150 mm) And discharged on a cooling roll at a roll temperature of 155 DEG C to prepare an unoriented film having a thickness of 160 mu m.

Subsequently, the unstretched film obtained above was cut into 96 mm x 96 mm, and extruded at a temperature of 178 캜 using a continuous biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., product number: X-6S) biaxial stretching was carried out in such a manner that the stretching ratio was doubled in the longitudinal direction (MD direction) and the transverse direction (TD direction) at the stretching speed of 1 / min. The stretched film obtained above was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆.

The in-plane retardation and thickness retardation of the optical film obtained above were 2.1 nm and -8.0 nm, respectively.

Subsequently, the absorptivity of the unstretched film and the retardation change value and the dimensional change rate in the thickness direction of the optical film obtained above were examined. The results are shown in Table 4.

From the results shown in Table 4, it can be seen that all of the optical films obtained in the respective Examples had excellent properties such that the water absorption rate of the unstretched film was low, the retardation value in the thickness direction of the stretched film and the dimensional change rate were small.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical films obtained in Examples 11 to 13 were examined. The results are shown in Table 5. The physical properties of these optical films were investigated in the same manner as in Example 1. The results are shown in Table 5.

From the results shown in Table 5, all of the optical films obtained in the Examples had low birefringence because they had good heat resistance, haze, total light transmittance, modulus and impact strength in MIT, The pencil hardness is high, and the absolute value of the photoelastic coefficient is small.

Example 14

70 parts by weight of ethyl methacrylate, 30 parts by weight of methacrylic acid, a mixed solvent of 78.8 parts by weight of toluene and 33.8 parts by weight of methanol as a polymerization solvent, and a mixed solvent of methanol and water were charged in a reaction part equipped with a stirrer, a temperature sensor, And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION) were charged, and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 6.4 parts by weight of toluene and 2.7 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aged for 4 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 30.2% by weight. The weight average molecular weight of the (meth) acrylic resin was 12.2 million.

Subsequently, a solution prepared by dissolving 0.1 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in the cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, .

The polymerization solution thus obtained was passed through a vent type screw twin-screw extruder (hole diameter: 15 mm) having a barrel temperature of 290 DEG C, a revolution of 160 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), one rear vent, Mm, L / D: 45) at a treatment rate of 420 g / h in terms of a resin amount, and devolatilization was carried out in this extruder and extrusion was carried out for about 3.6 minutes in the axial retention time to obtain pellets of a transparent (meth) acrylic resin.

The (meth) acrylic resin obtained above had a weight average molecular weight of 11.3 million and a glass transition temperature of 109 占 폚.

Subsequently, the pellet obtained above was extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 420 g / h in terms of a resin amount, and aniline was injected from the back of the hopper at a charging rate of 202 g / h by a liquid addition pump and extruded at an in- Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 10.1 million. The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R (Meth) acrylic resin having a repeating unit in which R ⁵ is a methyl group and R ⁶ is an ethyl group and has a glass transition temperature of 168 ° C.

The imidization ratio of the (meth) acrylic resin obtained above was 54.6%, the content of the repeating unit represented by the formula (II) was 26.0% by weight, and the stress optical coefficient (Cr) was 0.02 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 0.88 mmol / g.

Subsequently, the pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), the T die temperature was adjusted to 290 deg. C and melt extrusion was carried out from a coat hanger type T die (width 150 mm) And discharged onto a cooling roll at a roll temperature of 163 DEG C to prepare an unoriented film having a thickness of 160 mu m.

Subsequently, the unstretched film obtained above was cut to a size of 96 mm x 96 mm and extruded at a temperature of 188 DEG C of 240 mm < 2 > using a sequential biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., biaxial stretching was carried out in such a manner that the stretching ratio was doubled in the longitudinal direction (MD direction) and the transverse direction (TD direction) at the stretching speed of 1 / min. The stretched film obtained above was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆.

The in-plane retardation and thickness retardation of the optical film obtained above were 0.4 nm and 1.4 nm, respectively.

Subsequently, the absorptivity of the unstretched film and the retardation change value and the dimensional change rate in the thickness direction of the optical film obtained above were examined. The results are shown in Table 6.

Example 15

60 parts by weight of n-butyl methacrylate, 40 parts by weight of methacrylic acid, 67.5 parts by weight of toluene as a polymerization solvent, and 45 parts by weight of methanol were mixed in a reaction part equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas- , And 0.05 part by weight of an antioxidant (trade name: ADEKASTAB 2112, manufactured by ADEKA CORPORATION), and the temperature was raised to 73 캜 while nitrogen gas was passed through the reaction part. 0.25 parts by weight of dimethyl-2,2'-azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added to the reaction part Azobis (2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a mixed solvent of 5.5 parts by weight of toluene and 3.6 parts by weight of methanol, Was dropwise added to the reaction part over a period of 2 hours while solution polymerization was carried out under reflux at about 71 to 76 ° C. After completion of dropwise addition of dimethyl-2,2'-azobis (2-methylpropionate) And aging was carried out over 5 hours.

The content of the repeating unit derived from methacrylic acid in the (meth) acrylic resin contained in the polymer solution obtained above was 40.1% by weight. The weight average molecular weight of the (meth) acrylic resin was 14.5 million.

Subsequently, a solution prepared by dissolving 0.1 part by weight of sodium methoxide as a catalyst (cyclization catalyst) in the cyclization condensation reaction in 9.9 parts by weight of methanol was added dropwise to the polymerization solution in the reaction part at a temperature of about 65 to 70 DEG C over 20 minutes, .

Subsequently, the polymerization solution obtained above was passed through a vent type screw twin-screw extruder having a barrel temperature of 290 DEG C, a rotation speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), a number of rear vents of 1, : 15 mm, L / D: 45) at a treatment rate of 420 g / h in terms of a resin amount, and subjected to devolatilization in the extruder and extruded at a retention time of about 3.6 minutes in the extruder to obtain pellets of transparent (meth) acrylic resin .

The (meth) acrylic resin thus obtained had a weight average molecular weight of 12.8 million and a glass transition temperature of 98 占 폚.

Subsequently, the pellet obtained above was extruded through a vent type screw twin screw extruder (hole diameter: 15 mm, L / D: 10 mm) having a barrel temperature of 290 DEG C, a rotational speed of 300 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg) 45) at a throughput rate of 456 g / h in terms of the resin amount, and aniline was injected from the back of the hopper by a liquid addition pump at a charging rate of 378 g / h and extruded to about 5.2 minutes in the axial direction, Meta) acrylic resin.

The weight average molecular weight of the (meth) acrylic resin obtained above was 10.7 million. The (meth) acrylic resin obtained in the above is a repeating unit represented by the formula (I) in which R ¹ is a methyl group, R ² is a hydrogen atom and R ³ is a phenyl group, and R ⁴ is a hydrogen atom and R ⁵ is a methyl group, R ⁶ is a n-butyl group, and has a glass transition temperature of 162 ° C.

The imidization ratio of the (meth) acrylic resin obtained above was 61.8%, the content of the repeating unit represented by the formula (II) was 22.6% by weight, and the stress optical coefficient (Cr) was 0.09 10 ^-9 Pa ^-1 . The acid value of the (meth) acrylic resin was 0.92 mmol / g.

Subsequently, the pellets obtained above were placed in a single screw extruder (hole diameter: 20 mm, L / D: 25), the T die temperature was adjusted to 285 캜 and melt extrusion was carried out from a coat hanger type T die (width 150 mm) And discharged on a cooling roll at a roll temperature of 155 DEG C to prepare an unoriented film having a thickness of 160 mu m.

Subsequently, the unstretched film obtained above was cut into 96 mm x 96 mm and extruded at a temperature of 182 DEG C at 240 DEG C using a sequential biaxial stretching machine (manufactured by TOYO SEIKI SEISAKUSHO Co., Ltd., product number: X-6S) biaxial stretching was carried out in such a manner that the stretching ratio was doubled in the longitudinal direction (MD direction) and the transverse direction (TD direction) at the stretching speed of 1 / min. The stretched film obtained above was quickly taken out from the test apparatus and cooled to obtain an optical film having a thickness of 40 탆.

The in-plane retardation and thickness retardation of the optical film obtained above were 1.2 nm and 6.1 nm, respectively.

Subsequently, the absorptivity of the unstretched film and the retardation change value and the dimensional change rate in the thickness direction of the optical film obtained above were examined. The results are shown in Table 6.

From the results shown in Table 6, it can be seen that all of the optical films obtained in the respective Examples had excellent properties such that the water absorption rate of the unstretched film was low, and the retardation value and the dimensional change rate in the thickness direction of the stretched film were small.

The in-plane retardation, the retardation in the thickness direction, the photoelastic coefficient and the linear expansion coefficient of the optical films obtained in Examples 14 and 15 were examined. The results are shown in Table 7. The physical properties of these optical films were also examined in the same manner as in Example 1. The results are shown in Table 7.

From the results shown in Table 7, all of the optical films obtained in the Examples had low birefringence because they had good heat resistance, haze, total light transmittance, modulus in the MIT and impact strength, The pencil hardness is high, and the absolute value of the photoelastic coefficient is small.

Claims (13)

Formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents a cyclic structure)
And a repeating unit represented by the formula (II):

(Wherein R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms)
(Meth) acrylic resin having a repeating unit represented by the following formula (1). The method according to claim 1,
(Meth) acrylic resin has 5 to 85% by weight of a repeating unit represented by the formula (I) and 15 to 95% by weight of a repeating unit represented by the formula (II). 3. The method according to claim 1 or 2,
(Meth) acrylic resin having a glass transition temperature of 120 DEG C or higher. 4. The method according to any one of claims 1 to 3,
Wherein the absolute value of the stress optical coefficient (Cr) is 0.3 x 10 < ^-9 > Pa < ^-1 & A method for producing the (meth) acrylic resin according to any one of claims 1 to 4,
Formula (II):

(Wherein R ⁴ and R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms)
(Meth) acrylic resin having a repeating unit represented by the following formula (1) is imidized with an imidizing agent. An optical film comprising the (meth) acrylic resin according to any one of claims 1 to 4. The method according to claim 6,
Wherein an in-plane retardation (Re) at a wavelength of 590 nm is 20 nm or less and an absolute value of a thickness direction retardation (Rth) is 20 nm or less. 8. The method according to claim 6 or 7,
The absolute value of photoelastic coefficient of the wavelength of light is 590㎚ optical film, characterized in that not more than 10 × 10 ^-12 ㎩ ^-1. 9. The method according to any one of claims 6 to 8,
And a coefficient of linear expansion at 60 to 100 캜 is 80 × 10 ^-6 K ^-1 or less. 9. The method according to any one of claims 5 to 8,
Wherein the film is a biaxially oriented film. The transparent conductive film according to any one of claims 6 to 10, wherein a transparent conductive layer is formed on at least one surface of the optical film. An image display apparatus having the optical film according to any one of claims 6 to 10. An image display device having the transparent conductive film according to claim 11.