KR20190125301A - Optical film and manufacturing method - Google Patents

Abstract

A core layer, the 1st skin layer provided in the one surface of the said core layer, and the 2nd skin layer provided in the other surface of the said core layer, The said core layer consists of a resin composition (A), The The first skin layer and the second skin layer are made of a resin composition (B) different from the resin composition (A), and the resin composition (A) is 80% by weight or more in the total amount of the resin composition (A) 100 An alicyclic structure-containing polymer of not more than% by weight, the resin composition (B) comprises at least 95% by weight and 100% by weight or less of an alicyclic structure-containing polymer in the total amount of the resin composition (B), viscosity ratio η Optical film whose _B (ave) / (eta) _A (ave) is 0.3 or more and 3.0 or less.

Description

Optical film and manufacturing method

TECHNICAL FIELD This invention relates to an optical film and its manufacturing method.

In order to provide various functions, an optical film may become a multilayered structure.

Moreover, the resin composition containing the polymer containing an alicyclic structure may be used as a material of the multilayer optical film which has a multilayered structure from the point which is excellent in transparency, dimensional stability, phase difference expression property, heat resistance, moisture resistance, etc. (Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-118698

As an optical film using the resin composition containing the polymer containing an alicyclic structure as a material, the film containing the 3-layered structure provided with the skin layer on both surfaces of a core layer is mentioned.

As a method of manufacturing the film containing such a three-layer structure, the method of co-extruding the material of a core layer and the material of a skin layer is mentioned, The film containing the three-layer structure manufactured by co-extrusion, Thickness may become nonuniform. If the thickness of the film is nonuniform, the film after stretching may have an uneven optical property.

Therefore, it is desired to reduce the nonuniformity (thickness nonuniformity) of the thickness of the optical film containing a 3-layered structure.

MEANS TO SOLVE THE PROBLEM This inventor discovered that the said subject is solved when the apparent viscosity which the material of a core layer has and the apparent viscosity which a material of a skin layer has is constant.

That is, the present invention is as follows.

[1] a core layer, a first skin layer provided on one surface of the core layer, and a second skin layer provided on the other surface of the core layer,

The core layer is made of a resin composition (A),

The first skin layer and the second skin layer are made of a resin composition (B) different from the resin composition (A),

The said resin composition (A) contains 80 weight% or more and 100 weight% or less of an alicyclic structure containing polymer in the whole quantity of the said resin composition (A),

The resin composition (B) comprises at least 95% by weight and 100% by weight of an alicyclic structure-containing polymer in the total amount of the resin composition (B),

The viscosity ratio _{η B (ave) / η A} (ave) is 0.3 or more than 3.0, an optical film.

However, eta _A (ave) and eta _B (ave) are computed from following formula (1) and formula (2), respectively.

η _A (ave) = (η _A (12) + η _A (24) + η _A (61) + η _A (122) + η _A (243) + η _A (608) + η _A (1216) + η _A (2432) + η _A (6080) + η _A (12160)) / 10 (1)

η _B (ave) = (η _B (12) + η _B (24) + η _B (61) + η _B (122) + η _B (243) + η _B (608) + η _B (1216) + η _{B (2432) + η B (} 6080) + η B (12160)) / 10 (2)

Where

η _A (12), η _A (24), η _A (61), η _A (122), η _A (243), η _A (608), η _A (1216), η _A (2432), η _A (6080), and η _A (12160) have an apparent shear rate of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080, and 12160 (1 / s) of the resin composition (A). Appearance viscosity (Pa * s) in 280 degreeC is respectively shown,

η _B (12), η _B (24), η _B (61), η _B (122), η _B (243), η _B (608), η _B (1216), η _B (2432), η _B (6080), and η _B (12160) are 280 of the resin composition (B) at apparent shear rates of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) The apparent viscosity (Pa * s) in ° C is shown, respectively.

[2] The optical film according to [1], in which the resin composition (A) contains an ester compound.

[3] The optical film according to [2], wherein the content of the ester compound in the resin composition (A) is 0.1% by weight or more and 10% by weight or less in the total amount of the resin composition (A).

[4] As a method for producing an optical film,

The optical film includes a core layer, a first skin layer provided on one surface of the core layer, and a second skin layer provided on the other surface of the core layer,

The core layer is made of a resin composition (A),

The said 1st skin layer and the said 2nd skin layer consist of resin composition (B) different from the said resin composition (A),

The said resin composition (A) contains 80 weight% or more and 100 weight% or less of an alicyclic structure containing polymer in the whole quantity of the said resin composition (A),

The resin composition (B) comprises at least 95% by weight and 100% by weight of an alicyclic structure-containing polymer in the total amount of the resin composition (B),

The viscosity ratio η _B (ave) / η _A (ave) is 0.3 or more and 3.0 or less,

The manufacturing method of the optical film containing the process of coextrusion the said resin composition (A) and the said resin composition (B).

However, eta _A (ave) and eta _B (ave) are computed from following formula (1) and formula (2), respectively.

η _A (ave) = (η _A (12) + η _A (24) + η _A (61) + η _A (122) + η _A (243) + η _A (608) + η _A (1216) + η _A (2432) + η _A (6080) + η _A (12160)) / 10 (1)

η _B (ave) = (η _B (12) + η _B (24) + η _B (61) + η _B (122) + η _B (243) + η _B (608) + η _B (1216) + η _B (2432) + η _B (6080) + η _B (12160)) / 10 (2)

Where

η _A (12), η _A (24), η _A (61), η _A (122), η _A (243), η _A (608), η _A (1216), η _A (2432), η _A (6080), and η _A (12160) have an apparent shear rate of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080, and 12160 (1 / s) of the resin composition (A). Appearance viscosity (Pa * s) in 280 degreeC is respectively shown,

η _B (12), η _B (24), η _B (61), η _B (122), η _B (243), η _B (608), η _B (1216), η _B (2432), η _B (6080), and η _B (12160) are 280 of the resin composition (B) at apparent shear rates of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) The apparent viscosity (Pa * s) in ° C is shown, respectively.

The optical film of this invention and the manufacturing method of an optical film can reduce thickness nonuniformity of the optical film containing a three-layered structure.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the optical film which is one Embodiment of this invention.
2 is a partial explanatory diagram of a capillary rheometer for measuring the apparent viscosity.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment and an example are shown and this invention is demonstrated in detail. However, this invention is not limited to embodiment and illustration shown below, It can change and implement arbitrarily in the range which does not deviate from the Claim of this invention, and the range of the equality.

In the following description, the "composition" may consist of only 1 type of substance, and may contain 2 or more types of substances.

[One. Optical film]

The optical film of this invention contains a core layer, the 1st skin layer provided in one surface of the said core layer, and the 2nd skin layer provided in the other surface of the said core layer.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the optical film which is one Embodiment of this invention. The optical film 100 is provided with the 1st skin layer 110, the 2nd skin layer 120, and the core layer 130, and is in 1st surface 130S1 which is one surface of the core layer 130. FIG. The first skin layer 110 is provided in contact with each other, and the second skin layer 120 is provided in contact with the second surface 130S2, which is the other surface of the core layer 130.

In the optical film of the present invention, the core layer is made of a resin composition (A), and the first skin layer and the second skin layer are made of a resin composition (B) different from the resin composition (A).

[1-1. Viscosity of resin composition]

When the average of the apparent viscosity of the resin composition (A) is η _A (ave) (Pa · s) and the average of the apparent viscosity of the resin composition (B) is η _B (ave) (Pa · s), the viscosity ratio η _B (ave) / η _A (ave) is 0.3 or more and 3.0 or less.

However, eta _A (ave) and eta _B (ave) are computed from following formula (1) and formula (2), respectively.

η _A (ave) = (η _A (12) + η _A (24) + η _A (61) + η _A (122) + η _A (243) + η _A (608) + η _A (1216) + η _A (2432) + η _A (6080) + η _A (12160)) / 10 (1)

η _B (ave) = (η _B (12) + η _B (24) + η _B (61) + η _B (122) + η _B (243) + η _B (608) + η _B (1216) + η _B (2432) + η _B (6080) + η _B (12160)) / 10 (2)

Where

η _A (12), η _A (24), η _A (61), η _A (122), η _A (243), η _A (608), η _A (1216), η _A (2432), η _A (6080), and η _A (12160) are 280 of the resin composition (A) at apparent shear rates of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s). Appearance viscosity (Pa * s) in degrees C is shown, respectively.

η _B (12), η _B (24), η _B (61), η _B (122), η _B (243), η _B (608), η _B (1216), η _B (2432), η _B (6080), and η _B (12160) is of said resin composition (B) at an apparent shear rate of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080, and 12160 (1 / s) The apparent viscosity (Pa * s) in 280 degreeC is shown, respectively.

In this specification, an apparent viscosity is a value in 280 degreeC measured by the capillary rheometer based on Japanese Industrial Standard (JIS) K7199.

2 is a partial explanatory diagram of a capillary rheometer for measuring the apparent viscosity.

The capillary rheometer measures the pressure in the barrel 210, the capillary 220 connected to the lower end of the barrel 210, the piston 230 for sliding the inside of the barrel 210, and the barrel 210. The pressure sensor 240 to measure is provided. After the sample is filled in the barrel 210 and the sample is dissolved, the piston 230 is extruded at a constant extrusion speed to discharge the molten sample from the capillary 220, and the pressure in the barrel at the time of discharge is measured. In FIG. 2, R represents the radius m of the barrel 210, r represents the radius m of the capillary 220, and L represents the length of the capillary 220.

The apparent viscosity η _ap (Pa · s) is given by the following formula from the apparent shear rate S _ap (1 / s) and the apparent shear stress tau ap (Pa).

　

The apparent shear rate S _ap (1 / s) and the apparent shear stress τ _ap (Pa) are given by the following equation.

Where P denotes the pressure Pa in the barrel, r denotes the radius of the capillary (m), L denotes the length of the capillary (m), and Q denotes the flow rate (m ³ / s). denotes the circumference.

The flow rate Q (m ³ / s) is given by the following equation when the extrusion speed of the piston is v (m / s).

Therefore, the apparent shear rate S _ap can be adjusted by adjusting the extrusion speed of the piston.

As a capillary rheometer, Toyo Seiki Co., Ltd. product "capolograph 1D" can be used, for example.

The viscosity ratio η _B (ave) / η _A (ave) is 0.3 or more, preferably 0.5 or more, more preferably 0.7 or more, 3.0 or less, preferably 2.0 or less, and more preferably 1.5 or less to be.

By the viscosity ratio η _B (ave) / η _A (ave) in the above range, the optical film of the present invention can be reduced in thickness unevenness.

The average of the apparent viscosity at 280 ° C of the resin composition (A) is not particularly limited, but is preferably 10 Pa · s or more, more preferably 100 Pa · s or more, preferably 1000 Pa · s or less. More preferably, it is 500 Pa * s or less.

Although the average of the apparent viscosity at 280 degreeC of a resin composition (B) does not have limitation in particular, Preferably it is 10 Pa.s or more, More preferably, it is 100 Pa.s or more, Preferably it is 1000 Pa.s or less More preferably, it is 500 Pa * s or less.

[1-2. Core layer]

[1-2-1. Resin composition (A)]

The core layer consists of a resin composition (A).

Resin composition (A) contains 80 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of resin composition (A).

(Alicyclic structure-containing polymer)

An alicyclic structure containing polymer is a polymer in which the structural unit of the polymer has an alicyclic structure. Resin containing such an alicyclic structure containing polymer is excellent in the performance, such as transparency, dimensional stability, phase difference expression property, and elongation at low temperature normally.

The alicyclic structure-containing polymer may be a polymer having an alicyclic structure in the main chain, a polymer having an alicyclic structure in the side chain, a polymer having an alicyclic structure in the main chain and the side chain, and a mixture of any two or more thereof. Especially, the polymer which has an alicyclic structure in a principal chain from a viewpoint of mechanical strength and heat resistance is preferable.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Especially, a cycloalkane structure and a cycloalkene structure are preferable from a mechanical strength and heat resistance viewpoint, and especially a cycloalkane structure is especially preferable.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly, per one alicyclic structure. Preferably it is 15 or less. If the number of carbon atoms constituting the alicyclic structure is within this range, the mechanical strength, heat resistance and moldability of the resin composition (A) are highly balanced.

The ratio of the structural unit which has an alicyclic structure in an alicyclic structure containing polymer can be selected according to the use purpose of the optical film of this invention. The proportion of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and 100% by weight or less. can do. If the ratio of the structural unit which has an alicyclic structure in an alicyclic structure containing polymer exists in this range, transparency and heat resistance of a resin composition (A) will become favorable.

Among the alicyclic structure-containing polymers, cycloolefin polymers (cyclic olefin polymers) are preferable. A cycloolefin polymer is a polymer which has a structure obtained by superposing | polymerizing a cycloolefin monomer. In addition, the cycloolefin monomer is a compound having a ring structure formed of carbon atoms and having a polymerizable carbon-carbon double bond in the ring structure. Examples of the polymerizable carbon-carbon double bond include carbon-carbon double bonds capable of polymerization such as ring-opening polymerization. In addition, examples of the ring structure of the cycloolefin monomers include monocyclic, polycyclic, condensed polycyclic, bridged rings, and polycyclic combinations thereof. Especially, a polycyclic cycloolefin monomer is preferable from a viewpoint of highly balancing the characteristics, such as dielectric properties and heat resistance of the polymer obtained.

Preferred among the cycloolefin polymers include norbornene polymers, monocyclic cyclic olefin polymers, cyclic conjugated diene polymers, and hydrides thereof. Among these, norbornene-based polymers are particularly suitable because of their good moldability.

Examples of norbornene-based polymers include ring-opening polymers of monomers having a norbornene structure and hydrides thereof; The addition polymer of the monomer which has a norbornene structure, and its hydride are mentioned. Examples of the ring-opening polymer of the monomer having a norbornene structure include a ring-opening homopolymer of one type of monomer having a norbornene structure, a ring-opening copolymer of two or more types of monomers having a norbornene structure, and norbornene A ring-opening copolymer with the monomer which has a structure, and the other monomer copolymerizable with this is mentioned. Moreover, as an example of the addition polymer of the monomer which has a norbornene structure, the addition homopolymer of one type of monomer which has a norbornene structure, the addition copolymer of 2 or more types of monomers which have a norbornene structure, and norbornene And an addition copolymer with a monomer having a structure and other monomers copolymerizable therewith. Among these, the hydride of the ring-opening polymer of the monomer having a norbornene structure is particularly suitable in view of moldability, heat resistance, low hygroscopicity, dimensional stability, light weight and the like.

Examples of monomers having a norbornene structure include bicyclo [2.2.1] hepto-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: Dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] deca-3-ene (common name: metanotetrahydrofluorene), tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10} ] dodeca-3-ene (common name: tetracyclododecene) and derivatives of these compounds (for example, those having a substituent on the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents are the same or different, and several may be couple | bonded with the ring. The monomer which has a norbornene structure may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

Examples of the polar group include a hetero atom and an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, carbonyloxycarbonyl group, epoxy group, hydroxyl group, oxy group, ester group, silanol group, silyl group, amino group, amide group, imide group, nitrile group and sulfonic acid group.

Examples of monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, cyclooctene and derivatives thereof; Cyclic conjugated dienes, such as cyclohexadiene and cycloheptadiene, and its derivative (s) are mentioned. The monomer which has a norbornene structure and the monomer which can ring-open copolymerize may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The ring-opening polymer of the monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of a ring-opening polymerization catalyst.

Examples of the monomer copolymerizable with the monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms and derivatives thereof such as ethylene, propylene and 1-butene; Cycloolefins and derivatives thereof such as cyclobutene, cyclopentene and cyclohexene; And non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene. Among these, alpha-olefin is preferable and ethylene is more preferable. In addition, the monomer which has a norbornene structure, and the monomer copolymerizable by addition may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The addition polymer of the monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of an addition polymerization catalyst.

The hydrogenated products of the above-mentioned ring-opening polymers and addition polymers preferably have carbon-carbon unsaturated bonds in the presence of a hydrogenation catalyst comprising a transition metal such as nickel, palladium, for example in a solution of these ring-opening polymers and addition polymers. Preferably it can be prepared by hydrogenation of 90% or more.

As an example of a monocyclic alicyclic structure containing polymer, the addition polymer of the cyclic olefin type monomer which has monocycles, such as cyclohexene, cycloheptene, and cyclooctene, is mentioned.

Examples of the cyclic conjugated diene polymer include polymers obtained by cyclization of addition polymers of conjugated diene monomers such as 1,3-butadiene, isoprene and chloroprene; 1,2- or 1,4-addition polymers of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene; And these hydrides.

Moreover, it is preferable that the molecule | numerator of the said alicyclic structure containing polymer does not contain a polar group in the alicyclic structure containing polymer mentioned above.

The weight average molecular weight (Mw) of an alicyclic structure containing polymer can be suitably selected according to the objective of use of an optical film, Preferably it is 10,000 or more, More preferably, it is 15,000 or more, More preferably, it is 20,000 or more, Preferably Is 100,000 or less, More preferably, it is 80,000 or less, More preferably, it is 50,000 or less. When the weight average molecular weight is in this range, the mechanical strength and moldability of the optical film are highly balanced.

The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3.5 or less More preferably, it is 3.0 or less, Especially preferably, it is 2.7 or less. By making molecular weight distribution more than the said lower limit, productivity of a polymer can be raised and manufacturing cost can be suppressed. Moreover, since the quantity of a low molecular weight component becomes small by using below an upper limit, relaxation at the time of high temperature exposure can be suppressed and stability of an optical film can be improved.

Here, the weight average molecular weight and the number average molecular weight are polyisoprene or polystyrene conversion, respectively, measured by gel permeation chromatography using cyclohexane as a solvent or toluene when the sample is not dissolved in cyclohexane. It is a weight average molecular weight and a number average molecular weight.

The proportion of the alicyclic structure-containing polymer in the resin composition (A) is at least 80% by weight, preferably at least 90% by weight, more preferably at least 92% by weight, particularly preferably at least 95% by weight, and 100% by weight. % Or less, Preferably it is 99.9 weight% or less, More preferably, it is 99 weight% or less, More preferably, it is 98 weight% or less.

(Optional ingredient)

In addition to an alicyclic structure containing polymer, a resin composition (A) can also contain arbitrary components.

The resin composition (A) preferably contains an ester compound. When the resin composition (A) contains an ester compound, it becomes possible to adjust the physical properties of the core layer to the desired physical properties. Moreover, the ease of processing of an optical film can be improved because a resin composition (A) contains an ester compound. More specifically, processing of the optical film by a laser can be made easy.

A resin composition (A) may contain an ester compound individually by 1 type, and may contain it in combination of 2 or more types of arbitrary ratios.

As an ester compound, a phosphoric acid ester compound, a carboxylic acid ester compound, etc. are mentioned, for example, Especially, a carboxylic acid ester compound is preferable.

As a phosphoric acid ester compound, a triphenyl phosphate, a tricresyl phosphate, a phenyl diphenyl phosphate is mentioned, for example.

As a carboxylic ester compound, aromatic carboxylic acid ester, aliphatic carboxylic acid ester, etc. are mentioned, for example.

Aromatic carboxylic acid esters are esters of aromatic carboxylic acids with alcohols.

As the aromatic carboxylic acid, for example, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid and the like can be used. An aromatic carboxylic acid may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

As alcohol, a linear or branched alkyl alcohol can be used, for example. As the alcohol, a monovalent alcohol having one hydroxyl group per molecule may be used, or a polyhydric alcohol having two or more hydroxyl groups per molecule may be used. Specific examples of the monohydric alcohol include n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, tert-pentanol, n-hexanol, isohexanol, n -Heptanol, isoheptanol, n-octanol, isooctanol, 2-ethylhexanol, n-nonanol, isononanol, n-decanol, isodecanol, lauryl alcohol, myristyl alcohol, palmityl Alcohol and stearyl alcohol are mentioned. In addition, specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 1,5- Hexanediol, 1,6-hexanediol, neopentylglycol, pentaerythritol. An alcohol may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

Aliphatic carboxylic acid esters are esters of aliphatic carboxylic acids with alcohols.

Examples of the aliphatic carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Aliphatic carboxylic acid may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

As an alcohol, the same example as what was illustrated as alcohol which can be used for an aromatic carboxylic acid ester is mentioned, for example. In addition, an alcohol may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

In addition, the number of ester bonds per molecule of an ester compound may be one, or two or more may be sufficient as it. Therefore, you may use a polyester compound as an ester compound, for example. A polyester compound can be manufactured by making monohydric acid or monohydric alcohol into a stopper as needed, and reacting a bivalent or more acid and a polyhydric alcohol.

It is preferable to include an aromatic ring in a molecule among the above-mentioned ester compounds, and it is especially preferable that the ester bond is couple | bonded with this aromatic ring. Therefore, among the ester compounds mentioned above, aromatic carboxylic acid esters such as benzoic acid ester, phthalic acid ester, isophthalic acid ester, terephthalic acid ester, trimellitic acid ester and pyromellitic acid ester are preferable, and benzoic acid ester is more preferable. Among the benzoic acid esters, diethylene glycol dibenzoate and pentaerythritol tetrabenzoate are particularly preferable.

Moreover, it is preferable that an ester compound can function as a plasticizer in a resin composition (A).

The molecular weight of an ester compound becomes like this. Preferably it is 300 or more, More preferably, it is 400 or more, More preferably, it is 500 or more, Preferably it is 2200 or less, More preferably, it is 1800 or less, More preferably, it is 1400 or less. Bleed-out can be suppressed by making the molecular weight of an ester compound more than the lower limit of the said range.

Moreover, melting | fusing point of an ester compound becomes like this. Preferably it is 20 degreeC or more, More preferably, it is 60 degreeC or more, More preferably, it is 100 degreeC or more, Preferably it is 180 degrees C or less, More preferably, it is 150 degrees C or less, More preferably, Is 120 degrees C or less. Bleed-out can be suppressed by making melting | fusing point of an ester compound more than the lower limit of the said range.

The content of the ester compound in the resin composition (A) is preferably 0.1% by weight or more, more preferably 1% by weight or more, even more preferably 2% by weight or more, preferably 10% by weight or less, more preferably Is 9% by weight or less, more preferably 8% by weight or less.

The resin composition (A) may also contain any component in addition to the alicyclic structure-containing polymer and the optionally contained ester compound. As an arbitrary component, For example, coloring agents, such as a pigment and dye; Fluorescent brighteners; Dispersants; Heat stabilizers; Light stabilizers; Ultraviolet absorbers; Antistatic agents; Antioxidants; Fine particles; Additives, such as surfactant, are mentioned. These components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

[1-2-2. Physical Properties of Resin Composition (A)]

The glass transition temperature (Tg _A ) of the resin composition (A) is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, even more preferably 120 ° C. or higher, preferably 190 ° C. or lower, and more preferably 180. Or less, more preferably 170 or less. When glass transition temperature exists in the said range, the optical film excellent in durability can be manufactured easily. For example, when an optical film is retardation film, durability of retardation film in high temperature environment can be improved by making glass transition temperature more than the lower limit of the said range. Moreover, extending | stretching process can be performed easily by using below an upper limit.

[1-2-3. Thickness of core layer]

The thickness of the core layer is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm. It is as follows.

[1-3. First skin layer and second skin layer]

The first skin layer and the second skin layer each consist of a resin composition (B). In the following description, the first skin layer and the second skin layer may be collectively referred to simply as a skin layer.

 [1-3-1. Resin composition (B)]

Resin composition (B) is a composition different from resin composition (A).

Although the resin composition (B) has the same content as the resin composition (A), the composition may be different from each other, or may be a component different from the resin composition (A) and the content component, but the content component and its content ratio are unclear. The composition may differ in physical properties (for example, melting point, glass transition temperature, or viscosity).

Resin composition (B) contains 95 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of resin composition (B).

As an alicyclic structure containing polymer contained in a resin composition (B), what is selected from the range demonstrated as alicyclic structure containing polymer which can be contained in a resin composition (A) can be used. Thereby, since the grade of shrinkage of a core layer and a skin layer at the time of temperature change can be made to the same grade, generation | occurrence | production of the wrinkle in an optical film can be prevented. Moreover, transparency and dimensional stability of an optical film can be improved by using an alicyclic structure containing polymer.

The proportion of the alicyclic structure-containing polymer in the resin composition (B) is at least 95% by weight, preferably at least 97% by weight, more preferably at least 98% by weight, particularly preferably at least 99% by weight, and 100% by weight. It is% or less, Preferably it is 99.9 weight% or less, More preferably, it is 99 weight% or less. By making the ratio of an alicyclic structure containing polymer more than the lower limit of the said range, adhesiveness of a core layer, a 1st skin layer, and a 2nd skin layer can be improved. Moreover, by making it below an upper limit, generation | occurrence | production of a difference between shrinkage | contraction of a core layer and shrinkage | contraction of a skin layer can be suppressed.

As arbitrary components which can be contained in a resin composition (B), the same example as the arbitrary components which can be contained in a resin composition (B) is mentioned. In addition, arbitrary components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

It is preferable that a resin composition (B) does not contain an ester compound substantially. Specifically, content of the ester compound in a resin composition (B) becomes like this. Preferably it is less than 1.0 weight%, More preferably, it is 0.5 weight% or less in whole quantity of a resin composition (B). Thereby, since the bleed out of an ester compound can be prevented, the roll used at the time of manufacture and conveyance of an optical film can be prevented from being contaminated with ester compound. The minimum of content of the ester compound with respect to a resin composition (B) can be 0 weight% or more.

The glass transition temperature (Tg _B ) of the resin composition (B) forming the skin layer is preferably 100 ° C or higher, more preferably 110 ° C or higher, still more preferably 120 ° C or higher, and preferably 190 ° C or lower. More preferably, it is 180 degrees C or less, More preferably, it is 170 degrees C or less. When glass transition temperature exists in the said range, the optical film excellent in durability can be manufactured easily. For example, when an optical film is retardation film, durability of retardation film in high temperature environment can be improved by making glass transition temperature more than the lower limit of the said range. Moreover, extending | stretching process can be performed easily by using below an upper limit.

And a glass transition temperature Tg _A of the resin composition (A) to form a core layer, the absolute value of the difference between the glass transition temperature of the resin composition (B) to form a skin layer Tg _B | Tg _A -Tg _B | is preferably Is 40 degrees C or less, More preferably, it is 20 degrees C or less, More preferably, it is 10 degrees C or less. Tg _A -Tg _B | Although the minimum in particular is not specifically limited, It can be more than 0 degreeC.

[1-3-2. Thickness of skin layer]

The thickness of the first skin layer or the second skin layer is preferably 0.1 μm or more, more preferably 1 μm or more, even more preferably 10 μm or more, preferably 100 μm or less, more preferably 50 μm. Hereinafter, More preferably, it is 30 micrometers or less. By making the thickness of a 1st skin layer or a 2nd skin layer more than the lower limit of the said range, shrinkage of a film can be suppressed.

Further, the ratio ((first skin layer or second skin layer) / core layer) to the thickness of the core layer of the first skin layer or the second skin layer is preferably 1/300 or more, and more preferably 1/30 or more, More preferably, it is 1/3 or more, Preferably it is 10 or less, More preferably, it is 5 or less, More preferably, it is two or less.

1-4. Characteristics and Dimensions of Optical Films]

Haze of an optical film becomes like this. Preferably it is 1% or less, More preferably, it is 0.8% or less, Especially preferably, it is 0.5% or less. By making haze a low value, the sharpness of the display image of the display apparatus incorporating an optical film can be improved. Here, haze can be measured with a turbidimeter based on JISK7361-1997. Specifically, it measures five places using Nippon Denshoku Industries Co., Ltd. "turbidimeter NDH-300A", and can obtain the average value calculated | required therefrom as a haze value.

In-plane retardation Re of an optical film and retardation Rth of a thickness direction can be arbitrarily set according to the use of an optical film. For example, when using an optical film as retardation film, the range of specific in-plane retardation Re becomes like this. Preferably it is 50 nm or more, Preferably it is 200 nm or less in measurement wavelength 550 nm. The retardation Rth in the specific thickness direction is preferably 50 nm or more, preferably 300 nm or less, at a measurement wavelength of 550 nm.

Here, in-plane retardation Re is a value represented by (nx-ny) x d. In addition, the retardation Rth of the thickness direction of a film is a value represented by {(nx + ny) / 2-nz} xd. Here, nx represents the refractive index of the direction which gives the largest refractive index in the direction (in-plane direction) perpendicular | vertical to the thickness direction of a film. ny represents the refractive index of the direction perpendicular to the direction of nx as the said in-plane direction of a film. nz represents the refractive index of the thickness direction of a film. d represents the thickness of the film.

It is preferable that an optical film is a elongate shape. The elongate shape means having a length of at least about 5 times or more with respect to the width direction of the film, and preferably having a length of 10 times or more, specifically, the degree of being wound to form the wound body and stored or transported. It is said to have a length of. There is no restriction | limiting in particular in the upper limit of the length of a long film, For example, it can be 100,000 times or less with respect to width.

The width of the optical film is preferably at least 700 mm, more preferably at least 1000 mm, even more preferably at least 1200 mm, preferably at most 2500 mm, more preferably at most 2200 mm, even more preferably at 2000 mm. It is as follows.

The thickness of the optical film is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less. to be.

 [2. Manufacturing Method of Optical Film]

An optical film can be manufactured by shape | molding the resin composition (A) used as the material of a core layer, and the resin composition (B) used as the material of a 1st skin layer and a 2nd skin layer in the shape of a film. Examples of the molding method include a melt molding method and a solution casting method. Examples of the melt molding method include a melt extrusion method that is molded by melt extrusion, and a press molding method, an inflation molding method, an injection molding method, a blow molding method, and a stretch molding method. Among these methods, the melt extrusion method, the inflation molding method, and the press molding method are preferable from the viewpoint of obtaining a film excellent in mechanical strength and surface precision. Especially, the melt-extruding method is especially preferable at the point which can reduce the quantity of residual solvent, and an efficient and simple manufacture is possible.

Among the melt extrusion methods, the coextrusion method is preferable. It is preferable that the manufacturing method of the optical film of this invention includes the process of coextruding a resin composition (A) and a resin composition (B). Examples of the coextrusion method include a coextrusion T-die method, a coextrusion inflation method, a coextrusion lamination method, and the like. Especially, the coextrusion T die method is preferable. The coextrusion T-die method includes a feed block method and a multi-manifold method, and a multi-manifold method is particularly preferable in that the thickness nonuniformity can be reduced.

Moreover, after manufacturing a core layer, a 1st skin layer, and a 2nd skin layer separately, you may bond together the manufactured core layer, a 1st skin layer, and a 2nd skin layer, and may manufacture an optical film.

In addition, when manufacturing an optical film, you may perform another process as needed, for example, you may perform the process of extending | stretching an optical film.

[3. Use of Optical Film]

There is no restriction | limiting in the use of the optical film of this invention, It can apply to arbitrary optical uses. In addition, this optical film may be used independently and may be used in combination with another arbitrary member. For example, you may incorporate it into display apparatuses, such as a liquid crystal display device, an organic electroluminescent display device, a plasma display device, a FED (field emission) display device, and an SED (surface electric field) display device.

In addition, you may use the optical film of this invention as a polarizer protective film, for example.

For example, you may obtain a circularly polarizing film by combining the optical film of this invention with a polarizer as retardation film.

Example

Hereinafter, an Example is shown and this invention is demonstrated concretely. However, this invention is not limited to the Example shown below, It can change and implement arbitrarily in the range which does not deviate from the Claim of this invention, and the range of the equality. In the following description, "%" and "parts" indicating amounts are by weight unless otherwise indicated. In addition, the operation demonstrated below was performed in normal temperature normal pressure atmosphere unless there is particular notice.

[Assessment Methods]

(Average of apparent viscosity)

The apparent viscosity of the sample was measured using a capillary rheometer ("Capillograph 1D" manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K7199.

The barrel with the capillary rheometer is 9.55 mm in diameter, the capillary is 10.0 mm in length, and 1.0 mm in diameter. The test temperature was 280 ° C, the sample was introduced into the barrel, and then preheated for 5 minutes, and then the piston was extruded at a predetermined extrusion rate. The extrusion speed of the piston was 1.0, 2.0, 5.0, 10, 20, 50, 100, 200, 500 or 1000 mm / min. When extruding the piston at extrusion speeds of 1.0, 2.0, 5.0, 10, 20, 50, 100, 200, 500 and 1000 mm / min, the apparent shear rates 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) are given to a sample.

Apparent shear rates were measured at extrusion speeds of 1.0, 2.0, 5.0, 10, 20, 50, 100, 200, 500 and 1000 mm / min, resulting in apparent shear rates 12, 24, 61, 122, 243, 608, 1216, 2432 It was set as the apparent viscosity of the sample in, 6080, and 12160 (1 / s). Apparent viscosity at 280 ° C. of the sample by calculating the arithmetic mean of the apparent viscosity of the sample at the obtained apparent shear rates 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) The average? (Ave) (Pa · s) was obtained. Represents the apparent viscosity average of from 280 ℃ calculated based on the resin composition (A) to form a core layer with η _A (ave), an apparent viscosity at 280 ℃ obtained with respect to the resin composition (B) which forms a skin layer of The average is represented by η _B (ave). The viscosity ratio (eta) _B (ave) / (eta) _A (ave) was computed from the average of the apparent viscosity in 280 degreeC of the obtained sample.

(Measurement of Film Thickness and Evaluation of Thickness Unevenness)

The thickness of the film was measured by a contact type thickness gauge (dial gauge manufactured by Mitsutoyo Corporation). Film thickness (micrometer) was measured about six places next to each other on the same straight line of the width direction of a film by 30 mm space | interval, and the average value of the film thickness in 6 places was made into the average thickness (micrometer) of a film.

The standard deviation (sigma) (micrometer) of the film thickness obtained at six places was computed, and film thickness nonuniformity was evaluated by the following reference | standard using the (sigma) value.

3: the best: σ <2.0

2: Good: 2.0 ≤ σ <5.0

1: Bad: 5.0 ≤ σ

Production Example 1 (Production of Cyclic Olefin Polymer Resin (B-1) as Resin Composition (B))

(Step A. Ring-opening polymerization step)

Dicyclopentadiene (henceforth "DCP"), tetracyclo dodecene (henceforth "TCD"), and metanotetrahydrofluorene (henceforth "MTF"), The monomer mixture containing the weight ratio 60/35/5 was prepared.

To the reactor substituted with nitrogen, 7 parts of the above monomer mixture (1 wt% based on the total amount of the monomers used for polymerization) and 1600 parts of cyclohexane were added, and 0.55 parts of tri-i-butylaluminum, 0.21 parts of isobutyl alcohol, 0.84 parts of diisopropyl ether as a reaction regulator and 3.24 parts of 1-hexene were added as a molecular weight regulator.

To this, 24.1 parts of a tungsten hexachloride solution having a concentration of 0.65% dissolved in cyclohexane were added and stirred at 55 ° C for 10 minutes.

Subsequently, 693 parts of said monomer mixture and 48.9 parts of tungsten hexachloride solutions of the concentration of 0.65% dissolved in cyclohexane were dripped continuously in the system over 150 minutes, maintaining reaction system at 55 degreeC.

Then, reaction was continued for 30 minutes and superposition | polymerization was complete | finished and the ring-opening polymerization reaction liquid containing a ring-opening polymer was obtained. After the completion of the polymerization, the polymerization conversion rate of the monomer measured by gas chromatography was 100% at the time of completion of the polymerization.

(Step B. Hydrogenation Step)

The obtained ring-opening polymerization reaction solution was transferred to a pressure resistant hydrogenation reactor, 1.4 parts of diatomaceous earth supported nickel catalysts ("T8400RL" manufactured by Nikki Chemical Co., Ltd., 57% of nickel loading) and 167 parts of cyclohexane were added, and the mixture was subjected to 180 ° C at a hydrogen pressure of 4.6 MPa. It reacted for 6 hours and obtained the reaction solution. The reaction solution was made of Rajiolite # 500 as a filter bed, filtered under pressure using a filter (Ishikawajima Harima Heavy Industries, product name "Hunderbag Filter") at a pressure of 0.25 MPa to remove the hydrogenated catalyst, and the ring-opening polymer. A colorless transparent hydrogenated solution containing hydrogenated product of was obtained.

(Step C. Filtration Step)

Subsequently, this hydrogenated solution was filtered sequentially with a filter ("Zeta plus filter 30H" manufactured by Kyono Corp., 0.5 µm to 1 µm of pore diameters), and another metal fiber filter (0.4 µm of pore diameter, manufactured by Nichidai Co., Ltd.). Filtration further removed the fine solids from the hydrogenated solution.

(Process D. Drying Process and Forming Process)

Next, this hydrogenated solution was dried at a temperature of 270 ° C and a pressure of 1 kPa or less using a cylindrical concentrated dryer (manufactured by Hitachi, Ltd.). Thereby, cyclohexane and other volatile components which are solvents were removed from the hydrogenated solution, and resin solid content was obtained. This resin solid content was extruded in the shape of a strand in the molten state from the die directly connected to the said concentrated dryer. After cooling the extruded resin solid content, it cut | disconnected with the pelletizer and obtained the pellet-shaped cyclic olefin polymer resin (B-1) containing the hydrogenated substance of a ring-opening polymer. The average η _B (ave) of the apparent viscosity of the cyclic olefin polymer resin (B-1) as the resin composition (B) was 373 Pa · s.

Production Example 2 (Manufacture of Cyclic Olefin Polymer Resin (A-1) as Resin Composition (A))

Pellets were prepared in the same manner as in Production Example 1 except that the weight ratio (DCP / TCD / MTF) of the monomer mixture containing DCP, TCD, and MTF was changed to 55/40/5 in Step A (the ring-opening polymerization step). Cyclic olefin polymer resin (A-1) was obtained. As for the cyclic olefin polymer resin (A-1) as the resin composition (A), the average η _A (ave) of the apparent viscosity was 318 Pa · s.

Production Example 3 (Preparation of Cyclic Olefin Polymer Resin Composition (A-2) as Resin Composition (A))

(Ring opening polymerization step and hydrogenation step)

The hydrogenated solution (H-1) was obtained similarly to process A (ring-opening polymerization process) and process B (hydrogenation process) of manufacture example 1.

(Addition step of ester compound)

To the obtained hydrogenated solution (H-1), two parts of pentaerythritol tetrabenzoate (molecular weight 552, melting point: 102.0 ° C to 106.0 ° C) is added and dissolved per 98 parts of the hydrogenated solution dry weight, and a hydrogenated solution containing an ester compound. Got.

(Filtration process)

Subsequently, the hydrogenated solution containing the obtained ester compound was sequentially filtered through a filter (Qinosa Co., Ltd. "ZetaPlus Filter 30H", pore diameter 0.5 µm to 1 µm), and a filter made of another metal fiber (manufactured by Nichida Corporation) It filtered further by 0.4 micrometer of pore diameters, and removed the small solid content from the hydrogenated solution containing an ester compound.

(Drying process and molding process)

Next, the hydrogenated solution containing this ester compound was dried at the temperature of 270 degreeC and the pressure of 1 kPa or less using cylindrical concentration dryer (made by Hitachi, Ltd.). Thereby, cyclohexane and other volatile components which are solvents were removed from the hydrogenated solution containing the ester compound, and resin solid content was obtained. This resin solid content was extruded in the shape of a strand in the molten state from the die directly connected to the said concentrated dryer. Extruded resin solid content was cut | disconnected by the pelletizer after cooling, and the pellet-shaped cyclic olefin polymer resin composition (A-2) containing the hydrogenated substance of a ring-opening polymer was obtained. As for the cyclic olefin polymer resin composition (A-2) as the resin composition (A), the average η _A (ave) of the apparent viscosity was 136 Pa · s.

Production Example 4 (Preparation of Cyclic Olefin Polymer Resin Composition (A-3) as Resin Composition (A))

Nitrogen atmosphere, tetracyclo [7.4.0.1 ^10,13 .0 ^2,7] deca--2,4,6,11- tetrahydro-tetraene (1,4-methanol -1,4,4a, 9a- tetrahydro-fluorenyl Common Name: Metanotetrahydrofluorene (MTF) 25 parts, tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] dodeca-3-ene (common name: tetracyclododecene (TCD)) ) 35 parts and 40 parts of tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene (DCP)) were polymerized with a metathesis ring-opening polymerization catalyst system, and then hydrogenated to give a monomer. The ring-opening copolymer hydrogenated product of the mixture (weight ratio: MTF / TCD / DCP = 25/35/40) was obtained. After the completion of the hydrogenation reaction, the hydrogenation catalyst was removed from the reaction solution to obtain a hydrogenated solution (H-2) of the ring-opening polymer. The hydrogenation rate of the hydrogenated product of this ring-opening copolymer was 99.9% or more, Mw was 38,100 and Tg was 137 degreeC.

In the step of adding the ester compound, the amount of pentaerythritol tetrabenzoate is changed to 5 parts per 95 parts by weight of the hydrogenated solution dry weight by using the hydrogenated solution (H-2) instead of the hydrogenated solution (H-1). A hydrogenated solution containing an ester compound was obtained in the same manner as in Production Example 3 except that the same operations as in the filtration step, drying step, and molding step in Production Example 3 were performed to provide a cyclic olefin polymer resin composition (A-3 ) The average η _A (ave) of the apparent viscosity of the cyclic olefin polymer resin composition (A-3) as the resin composition (A) was 100 Pa · s.

Example 1

A film melt extrusion molding machine (column type, manufactured by GSI Creos Co., Ltd.) for coextrusion, which had two screw extruders having a screw diameter of 20 mmφ, a compression ratio of 3.1, and L / D = 30, was prepared. The film melt extrusion molding machine includes a T die, the T die has three layers, a lamination method is a multi-manifold type, and a flow path shape is a hanger type.

The cyclic olefin polymer resin (B-1) obtained in Production Example 1 and the cyclic olefin polymer resin (A-1) obtained in Production Example 2 were subjected to a die lip of 0.8 mm and a T die using the film melt extrusion molding machine. Molded into a film shape under the conditions of a width of 300 mm, a temperature of 260 DEG C of the molten resin composition and a cooling roll temperature of 110 DEG C, (the first skin layer made of a cyclic olefin polymer resin (B-1)) / (cyclic olefin polymer) The optical film provided with the core layer consisting of resin (A-1)) / (2nd skin layer consisting of ring type olefin polymer resin (B-1)) in this order was obtained. The thickness ratio of each layer was determined from the feed amount from the feeder of the screw extruder, and the first skin layer made of resin (B-1): the core layer made of resin (A-1): the second skin layer made of resin (B-1). This was set to be 1: 1: 1.

The average value of the total thickness of the obtained optical film was 33 micrometers. The results are shown in Table 1.

Example 2

A cyclic olefin polymer resin (B-1) was prepared in the same manner as in Example 1 except that the cyclic olefin polymer resin composition (A-2) obtained in Production Example 3 was used instead of the cyclic olefin polymer resin (A-1). 1) skin layer) / (core layer made of cyclic olefin polymer resin composition (A-2)) / (second skin layer made of cyclic olefin polymer resin (B-1)) An optical film was obtained. The thickness ratio of each layer was determined from the feed rate from the feeder of the screw extruder, and the first skin layer made of resin (B-1): the core layer made of resin (A-2): the second skin layer made of resin (B-1). This was set to be 1: 1: 1.

The average value of the total thickness of the obtained optical film was 33 micrometers. The results are shown in Table 1.

Comparative Example 1

Except for using the cyclic olefin polymer resin composition (A-3) obtained in Production Example 4 instead of the cyclic olefin polymer resin (A-1), the same procedure as in Example 1 was carried out (cyclic olefin polymer resin (B-1) 1) skin layer consisting of (core layer made of cyclic olefin polymer resin composition (A-3)) / (second skin layer made of cyclic olefin polymer resin (B-1)) An optical film was obtained. The thickness ratio of each layer is determined from the feed amount from the feeder of the screw extruder, and the first skin layer made of resin (B-1): the core layer made of resin (A-3): the second skin layer made of resin (B-1). This was set to be 1: 1: 1.

The average value of the total thickness of the obtained optical film was 34 micrometers. The results are shown in Table 1.

From Table 1, the viscosity ratio _{η B (ave) / η A} (ave) is, carried out in the range between 0.3 3.0 Examples 1 and 2, the optical film, and a viscosity ratio η _B (ave) of / η _A ( Compared with the optical film of the comparative example 1 in which ave) is larger than 3.0, it turns out that thickness nonuniformity is reduced.

100: optical film
110: first skin layer
120: second skin layer
130: core layer

Claims (4)

A core layer, a first skin layer provided on one surface of the core layer, and a second skin layer provided on the other surface of the core layer,
The core layer is made of a resin composition (A),
The said 1st skin layer and the said 2nd skin layer consist of resin composition (B) different from the said resin composition (A),
The said resin composition (A) contains 80 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of the said resin composition (A),
The said resin composition (B) contains 95 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of the said resin composition (B),
The viscosity ratio _{η B (ave) / η A} (ave) is 0.3 or more than 3.0, an optical film.
However, eta _A (ave) and eta _B (ave) are computed from following formula (1) and formula (2), respectively.
η _A (ave) = (η _A (12) + η _A (24) + η _A (61) + η _A (122) + η _A (243) + η _A (608) + η _A (1216) + η _A (2432) + η _A (6080) + η _A (12160)) / 10 (1)
η _B (ave) = (η _B (12) + η _B (24) + η _B (61) + η _B (122) + η _B (243) + η _B (608) + η _B (1216) + η _B (2432) + η _B (6080) + η _B (12160)) / 10 (2)
Where
η _A (12), η _A (24), η _A (61), η _A (122), η _A (243), η _A (608), η _A (1216), η _A (2432), η _A (6080), and η _A (12160) have an apparent shear rate of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080, and 12160 (1 / s) of the resin composition (A). Appearance viscosity (Pa * s) in 280 degreeC is respectively shown,
η _B (12), η _B (24), η _B (61), η _B (122), η _B (243), η _B (608), η _B (1216), η _B (2432), η _B (6080), and η _B (12160) are 280 of the resin composition (B) at apparent shear rates of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) The apparent viscosity (Pa * s) in ° C is shown, respectively. The method of claim 1,
Optical film in which a resin composition (A) contains an ester compound. The method of claim 2,
The optical film whose content of the ester compound in the said resin composition (A) is 0.1 weight% or more and 10 weight% or less in whole quantity of the said resin composition (A). As a manufacturing method of an optical film,
The optical film includes a core layer, a first skin layer provided on one surface of the core layer, and a second skin layer provided on the other surface of the core layer,
The core layer is made of a resin composition (A),
The said 1st skin layer and the said 2nd skin layer consist of resin composition (B) different from the said resin composition (A),
The said resin composition (A) contains 80 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of the said resin composition (A),
The said resin composition (B) contains 95 weight% or more and 100 weight% or less of alicyclic structure containing polymer in the whole quantity of the said resin composition (B),
The viscosity ratio η _B (ave) / η _A (ave) is 0.3 or more and 3.0 or less,
The manufacturing method of the optical film containing the process of coextrusion the said resin composition (A) and the said resin composition (B).
However, eta _A (ave) and eta _B (ave) are computed from following formula (1) and formula (2), respectively.
η _A (ave) = (η _A (12) + η _A (24) + η _A (61) + η _A (122) + η _A (243) + η _A (608) + η _A (1216) + η _A (2432) + η _A (6080) + η _A (12160)) / 10 (1)
η _B (ave) = (η _B (12) + η _B (24) + η _B (61) + η _B (122) + η _B (243) + η _B (608) + η _B (1216) + η _B (2432) + η _B (6080) + η _B (12160)) / 10 (2)
Where
η _A (12), η _A (24), η _A (61), η _A (122), η _A (243), η _A (608), η _A (1216), η _A (2432), η _A (6080), and η _a (12160) is of the resin composition (a) at an apparent shear rate of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080, and 12160 (1 / s) Appearance viscosity (Pa * s) in 280 degreeC is respectively shown,
η _B (12), η _B (24), η _B (61), η _B (122), η _B (243), η _B (608), η _B (1216), η _B (2432), η _B (6080), and η _B (12160) are 280 of the resin composition (B) at apparent shear rates of 12, 24, 61, 122, 243, 608, 1216, 2432, 6080 and 12160 (1 / s) The apparent viscosity (Pa * s) in ° C is shown, respectively.

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