JP6225685B2 - Resin composition and optical film - Google Patents

Description

  The present invention relates to a resin composition and an optical film.

  As the polarizing plate, a polarizing film obtained by dyeing and stretching a polyvinyl alcohol (PVA) film may be used. On such a polarizing plate, a protective film of celluloses such as triacetyl cellulose (TAC) is laminated (see JP 2002-131536 A). Moreover, in order to compensate for the high hygroscopicity, which is a drawback when TAC is used as a protective film, and to reduce the weather resistance resulting therefrom, and to perform optical compensation, a retardation film formed from a cyclic olefin resin is formed on the protective film. Lamination is also considered.

  In recent years, modified TACs such as N-TAC (Konica Minolta Opto) and V-TAC (Fuji Film) have been used to provide optical compensation functions such as viewing angle expansion while maintaining the protective function of TAC polarizing films. A modified TAC film has been developed. However, these modified TAC films have insufficient retardation and low moisture resistance, and are not sufficient to prevent the occurrence of optical distortion due to environmental changes such as high temperature and high humidity.

  On the other hand, the cyclic olefin resin has a high glass transition temperature due to the rigidity of the main chain structure, and an optical compensation film such as a retardation film formed from the cyclic olefin resin has a retardation development property and low water absorption. Excellent in properties. Therefore, it is considered that the retardation can be sufficiently expressed by forming an optical compensation film using a resin in which a cyclic olefin-based resin and celluloses are mixed. Such an optical compensation film does not need to be laminated with a modified TAC film and a retardation film. Therefore, it is possible to reduce costs by reducing the viewing angle and heat unevenness due to insufficient lamination accuracy.

  However, it is generally known that it is difficult to blend polymers together to make them compatible. If the compatibilization between the polymers is insufficient, the film formed from such a resin is clouded and has low light transmittance, making it difficult to use as an optical film.

JP 2002-131536 A

  The present invention has been made based on the above circumstances, and a polymer containing a structure derived from a cyclic olefin in the main chain and a modified cellulose are preferably compatibilized and suitable for an optical film such as an optical compensation film. It aims at providing the resin composition which can be used for.

  As a result of intensive studies in order to solve the above problems, the present inventor uses a modified cellulose having a specific structural unit, so that the modified cellulose is suitable for a polymer containing a structure derived from a cyclic olefin in the main chain. The present invention was found out to be compatible with the present invention.

（式（１）中、Ｒ^１〜Ｒ^３は、それぞれ独立して、水素原子又は１価の置換基である。但し、上記置換基は、酸素原子、硫黄原子、窒素原子若しくはケイ素原子を含んでいてもよい２〜２０のアシル基、及びスルホニル基を含む１価の基からなる群から選択される少なくとも１種である。上記第２構造単位における上記置換基による総置換度は、０．５〜３である。） The invention made to solve the above problems is
A polymer having a first structural unit derived from a cyclic olefin in the main chain (hereinafter also referred to as “(A) polymer”), and a modified cellulose having a second structural unit represented by the following formula (1) (hereinafter referred to as “(A) polymer”) It is a resin composition containing “(B) modified cellulose”.

(In Formula (1), R < ¹ > -R < ³ > is respectively independently a hydrogen atom or a monovalent substituent. However, the said substituent contains an oxygen atom, a sulfur atom, a nitrogen atom, or a silicon atom. And at least one selected from the group consisting of a monovalent group containing 2 to 20 acyl groups and a sulfonyl group, and the total degree of substitution by the substituents in the second structural unit is 0. 5-3.)

  The present invention includes an optical film formed from the resin composition.

  In the resin composition of the present invention, the modified cellulose having a specific structural unit is suitably compatibilized with a polymer having a structural unit derived from a cyclic olefin in the main chain. Since the optical film of the present invention is formed using a resin composition in which polymers are suitably compatible with each other, the white turbidity of the film is suppressed and the light transmittance is high. In addition, the resin composition contains the polymer and the specific modified cellulose, so that a sufficient phase difference is developed and water absorption can be lowered, so that optical distortion due to environmental changes such as high temperature and high humidity can be reduced. Generation can be suppressed. In addition, since the optical film is a polymer that is compatible with each other, the viewing angle is reduced due to insufficient lamination accuracy, heat unevenness, etc., compared to the case where each polymer is individually filmed and laminated. It is possible to reduce the cost and reduce the cost.

  Hereinafter, the resin composition and the optical film of the present invention will be described.

<Resin composition>
The resin composition of the present invention contains (A) a polymer and (B) a modified cellulose. The said resin composition may contain antioxidant, a ultraviolet absorber, and other arbitrary components in the range which does not impair the effect of this invention.

[(A) Polymer]
(A) A polymer is a cyclic olefin polymer. Cyclic olefin polymers are generally excellent in optical properties such as transparency, dimensional stability and heat resistance, and are used in various fields in addition to optical applications. (A) A polymer contains the structural unit (henceforth "structural unit (a)") derived from a cyclic olefin in a principal chain among cyclic olefins. That is, the (A) polymer comprises a polymer comprising a structural unit (a) derived from a cyclic olefin, and a structural unit (a) derived from a cyclic olefin and a structural unit derived from another monomer. Includes both polymers. The polymer (A) includes monomer addition polymers, ring-opening metathesis polymers, and hydrogenated products thereof. As said structural unit (a), the structural unit represented, for example by following formula (2) is mentioned.

In the above formula (2), R ^{4 to} R ⁷ are each independently the following (i) to (vi). However, R ^{4 to} R ⁷ may be the following (vii) or (viii). p and m are each independently an integer of 0 to 3.

(I) a hydrogen atom (ii) a halogen atom (iii) a trialkylsilyl group (iv) a substituted or unsubstituted 1-30 hydrocarbon group having a linking group containing an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom ( v) A substituted or unsubstituted 1-30 hydrocarbon group (excluding (iv))
(Vi) a group containing a polar group (excluding (iv) and (v))
(Vii) An alkylidene group formed by combining R ⁴ and R ⁵ with each other or R ⁶ and R ⁷ with each other. (However, R ⁴ and R ⁵ , or R ⁶ and R ⁷ , which are not involved in the mutual bond, are each independently any atom or group of (i) to (vi) above)
(Viii) At least two of R ^{4 to} R ⁷ are bonded to each other to form a monocyclic or polycyclic hydrocarbon ring or heterocyclic ring together with the carbon to which they are bonded. (However, R ^{4 to} R ⁷ , which are not involved in the mutual bond among R ^{4 to} R ⁷ , are each independently any atom or group of (i) to (v) above).

  As said (iii) trialkylsilyl group, a C1-C12 trialkylsilyl group etc. are mentioned, for example, A C1-C6 trialkylsilyl group is preferable. Examples of such a trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and the like.

Examples of the linking group containing an oxygen atom, sulfur atom, nitrogen atom or silicon atom in (iv) above include a carbonyl group (—CO—), an oxycarbonyl group (—OCO—), a carbonyloxy group (—COO—), Sulfonyl group (—SO ₂ —), ether bond (—O—), thioether bond (—S—), imino group (—NH—), amide bond (—NHCO—, —CONH—), siloxane bond (—OSi) (R) _2- (wherein R is an alkyl group such as methyl or ethyl)). In addition, the hydrocarbon group having 1 to 30 carbon atoms in (iv) may include a plurality of linking groups.

Examples of the unsubstituted hydrocarbon group having 1 to 30 carbon atoms in (iv) and (v) include, for example, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an i-butyl group, and a t-butyl group. Monovalent chain hydrocarbon groups such as n-pentyl group;
Monovalent alicyclic hydrocarbon groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a dicyclopentyl group, a tricyclodecyl group, a tetracyclododecyl group, an adamantyl group;
And monovalent aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, an anthryl group, and a biphenyl group.

  Examples of the substituted hydrocarbon group having 1 to 30 carbon atoms in (iv) and (v) include those exemplified as the unsubstituted hydrocarbon group having 1 to 30 carbon atoms in (iv) and (v) above. A hydrocarbon group in which at least one of the hydrogen atoms is substituted with a substituent is exemplified. Examples of the substituent include a halogen atom, hydroxy group, carboxy group, cyano group, nitro group, halogenated hydrocarbon group, alkyl group, alkoxyl group, amino group, thiol group, and organic sulfonyl group.

  (Vi) Examples of the polar group include a hydroxy group; an alkoxy group having 1 to 10 carbon atoms such as a methoxy group and an ethoxy group; an acyloxy group such as an acetoxy group, a propionyloxy group and a benzoyloxy group; a cyano group; an amino group; Group; sulfo group; carboxyl group and the like.

  Examples of the alkylidene group formed by the mutual bond in (vii) above include a methylidene group, an ethylidene group, and a propylidene group.

  Examples of the monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by the mutual bond in (viii) above include, for example, cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclobutene ring, cyclopentene Ring, cyclohexene ring, benzene ring, naphthalene ring and the like.

The polymer (A) preferably contains at least one group of (iv) and (vi) as R ^{4 to} R ⁷ from the viewpoint of compatibility with the modified cellulose.

  Examples of the structural unit (a) include structural units represented by the following formulas (3-1) to (3-15).

  (A) The polymer may contain one type of structural units (a) represented by the above formulas (3-1) to (3-15), or may contain a plurality of types.

  (A) As a content rate of the structural unit (a) in a polymer, 50 mol% or more and 100% or less are preferable with respect to all the structural units in (A) polymer, and 75 mol% or more and 100% or less are more. preferable.

  (A) The intrinsic viscosity [η] of the polymer is usually 0.2 dL / g to 5.0 dL / g, preferably 0.3 dL / g to 4.0 dL / g, more preferably 0.35 dL / g. -1.5 dL / g. The intrinsic viscosity [η] is a value measured in a 30 ° C. chlorobenzene solution (concentration 0.5 g / 100 mL).

  (A) The number average molecular weight (Mn) of a polymer is 8,000-1,000,000 normally, Preferably it is 10,000-500,000, More preferably, it is 20,000-100,000. (A) The weight average molecular weight (Mw) of a polymer is 10,000-3,000,000 normally, Preferably it is 20,000-1,000,000, More preferably, it is 30,000-500,000. (A) When the number average molecular weight (Mn) or weight average molecular weight (Mw) of a polymer is too small, there exists a possibility that the intensity | strength of the molded article and film obtained may become low. On the other hand, if the number average molecular weight (Mn) or the weight average molecular weight (Mw) of the polymer (A) is too large, the solution viscosity or melt viscosity becomes too high and the productivity and workability of the resin composition of the present invention deteriorate. There is a risk.

  In addition, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of (A) polymer are polystyrene conversion values measured by gel permeation chromatography (GPC).

  (A) The molecular weight distribution (Mw / Mn) of the polymer is usually from 1.5 to 10, preferably from 2 to 8, more preferably from 2.2 to 5.

  (A) The glass transition temperature (Tg) of the polymer is usually 110 ° C to 250 ° C, preferably 115 ° C to 220 ° C, more preferably 120 ° C to 200 ° C. (A) If the Tg of the polymer is too low, the heat distortion temperature becomes low, which may cause a problem in heat resistance, and changes in optical properties due to the temperature of a molded article such as a film obtained from the resin composition. May increase. On the other hand, if the Tg of the polymer (A) is too high, it is necessary to increase the processing temperature, and the resin composition may be thermally deteriorated during processing.

  The content of the polymer (A) in the resin composition is usually 25% by mass or more and 99.9% by mass or less, preferably 25% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 60% by mass or less. is there. When the content of the polymer (A) is less than 25% by mass, the properties of the cyclic olefin polymer, such as transparency and heat resistance, may not be sufficiently obtained, and the water absorption due to the properties of (B) the modified cellulose. There is a risk of increasing the performance. If the content of (A) polymer exceeds 99.9% by mass, the advantageous properties of (B) modified cellulose may not be sufficiently exhibited.

[(B) Modified cellulose]
(B) The modified cellulose has a structural unit represented by the following formula (1) (hereinafter also referred to as “structural unit (b)”). This (B) modified cellulose may contain other structures as long as the effects of the present invention are not impaired.

In the above formula (1), R ^{1 to} R ³ are each independently a hydrogen atom or a monovalent substituent. However, the substituent (hereinafter also referred to as “substituent (b1)”) is an acyl group having 2 to 20 carbon atoms which may contain an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom, and 2 to 2 carbon atoms. It is at least one selected from the group consisting of 20 organic sulfonyl groups. The total degree of substitution by the substituent (b1) in the structural unit (b) is 0.5-3. The total degree of substitution is preferably 1 or more, more preferably 2 or more, further preferably 2.5 or more, and particularly preferably 3.

Here, the total degree of substitution refers to a ratio in which the hydrogen atoms of R ^{1 to} R ³ are substituted with the acyl group and the organic sulfonyl group. For example, a total degree of substitution of 0.5 means that only one of the six hydrogen atoms of R ^{1 to} R ^{3 in} the two structural units (b) is substituted with the acyl group or the organic sulfonyl group. Means that A total degree of substitution of 3 means that all ^three R ^{1 to} R ³ of one structural unit (b) are the acyl group and / or the organic sulfonyl group.

  Examples of the acyl group having 2 to 20 carbon atoms as the substituent (b1) include linear acyl groups such as acetyl group, propionyl group, butyroyl group, pentanoyl group (valeryl group); isopropionyl group, isobutyroyl group, isovaleryl Groups, branched acyl groups such as bivaloyl groups; cyclic alkanoyl groups such as cyclopentanoyl groups, cyclohexanoyl groups and cycloheptanoyl groups; aromatic acyls such as benzoyl groups, phenylacetyl groups, phenylpropanoyl groups and naphthanoyl groups Group and the like. When the acyl group having 2 to 20 carbon atoms contains an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom, these atoms may be present as a linking group between carbon-carbon bonds, and are part of the functional group May exist as

The organic sulfonyl group as the substituent (b1) is a sulfonyl group having a monovalent organic group bonded thereto. Examples of the monovalent organic group include a substituted or unsubstituted monovalent hydrocarbon group. Examples of the substituted or unsubstituted monovalent hydrocarbon group include those exemplified as the substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms represented by R ^{4 to} R ⁷ in the above formula (1). The same thing is mentioned.

  At least one of the substituents (b1) of the structural unit (b) includes a monovalent group represented by the following formula (4) (hereinafter also referred to as “substituent (b1-1)”). Is preferred. Since the (B) modified cellulose containing such a substituent (b1-1) can form a hydrogen bond with the carbonyl group or the like of the (A) polymer, it is more excellent in compatibility with the (A) polymer. In addition, the group which can form the hydrogen bond represented by following formula (4) may have the structural unit (a) of (A) polymer. That is, in the resin composition, the (A) polymer and (B) modified cellulose are preferably a combination capable of forming a hydrogen bond between them.

In the above formula (4), Z represents an oxygen atom, a sulfur atom, —O—R ⁸ —O—, —S—R ⁸ —S—, or —O—R ⁸ —S—. R ⁸ is a divalent linking group having 1 to 4 carbon atoms.

  As the substituent (b1-1), a group containing a phenyl hydroxyl group such as a hydroxybenzoyl group or (hydroxyphenyl) acetyl group, a group containing a thiophenolic thiol group such as a mercaptobenzoyl group or (mercaptophenyl) acetyl group, A group containing an alcoholic hydroxyl group is preferred, and a group containing a phenyl hydroxyl group is more preferred.

  When the substituent (b1-1) is included in at least one of the substituents (b1) of the structural unit (b), the degree of substitution by the substituent (b1) including the substituent (b1-1) is as follows: 0.1-2.0 are preferable and 0.2-1.0 are more preferable. If the degree of substitution is less than 0.1, the compatibility of the resin composition tends to decrease, and the transparency of the optical film tends to be impaired. On the other hand, when the degree of substitution exceeds 2.0, there is a tendency for water absorption to deteriorate and coloring.

  (B) As a content rate of the structural unit (b) in modified cellulose, 50 mol% or more and 100% or less are preferable with respect to all the structural units in (B) modified cellulose, and 75 mol% or more and 100% or less are more. preferable.

  The total light transmittance when the resin composition is made into a film having a thickness of 200 μm is preferably 90% or more. If the total light transmittance is less than 90%, it may be difficult to apply to uses such as optical films that require transparency.

  The content of (B) modified cellulose in the resin composition is usually 0.01 parts by mass or more and 300 parts by mass or less, preferably 10 parts by mass or more and 300 parts by mass or less, with respect to 100 parts by mass of the polymer (A). More preferably, it is 40 to 150 mass parts. (B) When content of a modified cellulose exists in the said range, it will be excellent in retardation development, a weather resistance, heat resistance, and water absorption resistance (low water absorption). (B) When the modified cellulose content is less than 0.01 parts by mass, the affinity with PVA is lost, and the adhesiveness when the optical film formed from the resin composition is adhered to the PVA polarizing film. May be low. On the other hand, if the content of (B) the modified cellulose exceeds 300 parts by mass, the retardation development, weather resistance, and heat resistance may decrease, and the water absorption may increase.

[Antioxidant]
Antioxidants improve heat deterioration resistance and weather resistance. Examples of the antioxidant include phenol-based or hydroquinone-based antioxidants and phosphorus-based antioxidants. An antioxidant may be used individually by 1 type, or may use 2 or more types together.

  Examples of the phenol-based or hydroquinone-based antioxidant include 2,6-di-tert-butyl-4-methylphenol, 2,2′-dioxy-3,3′-di-tert-butyl-5,5′-. Dimethyldiphenylmethane, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like.

  Examples of phosphorus antioxidants include tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, and the like. It is done.

[Ultraviolet absorber]
The ultraviolet absorber improves light resistance. Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6-[( 2H-benzotriazol-2-yl) phenol]] and the like.

[Other optional ingredients]
The said resin composition may contain other arbitrary components other than (A) polymer, (B) modified cellulose, antioxidant, and a ultraviolet absorber. Examples of the other optional components include known additives such as a flame retardant, an antibacterial agent, a colorant, a release agent, and a foaming agent in addition to a lubricant that improves processability. These other optional components may be used alone or in combination of two or more.

[Method for Preparing Resin Composition]
The resin composition includes, for example, (i) (A) a polymer, (B) a modified cellulose, an antioxidant, an ultraviolet absorber, and other optional components as necessary. Using and mixing methods,
(Ii) (A) A polymer, (B) a modified cellulose, and if necessary, an antioxidant and other optional components can be produced by mixing them in a solution dissolved in an appropriate solvent.

<Optical film>
The optical film according to the present invention is formed from the resin composition. Examples of the optical film include a retardation film, a polarizing film, and a light diffusion film.

[Thickness of optical film]
The thickness of the optical film is appropriately selected depending on the application and the like, but is usually 500 μm or less, preferably 10 μm to 300 μm, more preferably 50 μm to 188 μm. If the thickness of the optical film is too small, the film strength may not be sufficiently secured. on the other hand. If the thickness of the optical film exceeds 500 μm, the transparency of the sheet may not be ensured.

[Total light transmittance of optical film]
The total light transmittance of the optical film is preferably 90% or more. Here, the total light transmittance is a value of a transparency test method (JIS-K7105: 1981) in the thickness of an optical film having a thickness of 200 μm. When the total light transmittance of the thickness of the optical film is 90% or more, the transparency of the polymer sheet can be ensured. Therefore, the said optical film can be used conveniently as a phase difference film, a polarizing film, etc. In addition, it is not preferable that the total light transmittance of the thickness of the optical film is less than 90% because a decrease in transparency becomes remarkable.

[Method for producing optical film]
The optical film can be produced by molding the resin composition into a film using a known molding method, for example, an injection molding method, a compression molding method, an extrusion molding method, or the like. Among these, the extrusion method is preferable, and the melt extrusion method described later is more preferable. Alternatively, (A) a polymer, (B) a modified cellulose, and if necessary, an optional component may be dissolved or dispersed in an appropriate solvent, and then a film may be formed by a solvent casting method. The solvent used at this time is usually used in the solvent casting method and is not particularly limited as long as it can sufficiently dissolve (A) the polymer, (B) the modified cellulose, and the like. For example, a polar solvent or a nonpolar solvent is used. be able to. Here, the polar solvent has a dielectric constant at 20 ° C. of 4 or more and less than 80, and the nonpolar solvent has a dielectric constant of 1 or more and less than 4.

(Melt extrusion method)
In the melt extrusion molding method, the resin composition is supplied to an extruder and melted, and the molten resin composition is extruded from a die and pressed onto a cooling roll to form an optical film.

  As a method of melting the resin composition, a method using an extruder is preferable. After the molten resin composition is supplied in a fixed amount by a gear pump, and filtered through a metal filter or the like to remove impurities, a film is formed by a die. A method of extruding while shaping into a shape is preferable.

  Examples of the extruder include a single screw extruder, a twin screw extruder, a planetary extruder, a kneader extruder, and the like, and a single screw extruder is preferable.

  As a die, it is necessary to make the resin flow inside the die uniform, and in order to keep the film thickness uniform, the pressure distribution inside the die near the die outlet needs to be constant in the width direction. It is. Examples of the die satisfying such conditions include a manifold die, a fish tail die, a coat hanger die, and the like, and among these, a coat hanger die is preferable.

  The cooling roll preferably has a heating means and a cooling means inside, and a material whose surface material is ceramic selected from aluminum oxide, tungsten carbide and chromium oxide is used. Of these, aluminum oxide is particularly preferable from the viewpoint of surface hardness and strength.

  In the method for producing the optical film, the optical film obtained by melt extrusion may be further stretched. Specifically, as a stretching method in that case, a known uniaxial stretching method or biaxial stretching method, for example, a horizontal uniaxial stretching method by a tenter method, an inter-roll compression stretching method, and two sets of rolls having different circumferences are used. Examples thereof include a longitudinal uniaxial stretching method, a biaxial stretching method in which a lateral uniaxial and a longitudinal uniaxial are combined, and a stretching method by an inflation method. The thickness of the optical film obtained by stretching is usually 200 μm or less, preferably 10 μm to 150 μm.

[Use of optical film]
The optical film is preferably used as a retardation film. Such a retardation film can be used as a polarizing plate by adhering to a polarizer. Specifically, on at least one surface of a polarizer composed of a PVA film or the like, an aqueous adhesive composed of an aqueous solution mainly composed of PVA resin, a polar group-containing adhesive, a photocurable adhesive, or the like is used. A polarizing plate can be obtained by laminating an optical film, heating or exposing it as necessary, pressure bonding, and bonding (laminating) the polarizer and the optical film.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example.

<Measurement and evaluation method>
(1) Intrinsic viscosity [η]
Intrinsic viscosity [η] was measured at 30 ° C. in a chlorobenzene solution having a concentration of 0.5 g / 100 mL.

(2) Molecular weight The molecular weight was measured using “HLC-8220 gel permeation chromatography” (GPC, columns (“TSKgel G7000HxL”, “TSKgelGMHxL”, “TSKgelGMHxL” and “TSKgelGMHxL” and “TSKgelG2000xL”)) manufactured by Tosoh Corporation. THF) solvent was measured as polystyrene-equivalent number average molecular weight (Mn) and weight average molecular weight (Mw). The molecular weight distribution (Mw / Mn) was calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw).

(3) Glass transition temperature (Tg)
The glass transition temperature was measured under a nitrogen stream using a “DSC6200” manufactured by Seiko Instruments Inc. with a heating rate of 20 ° C. per minute. Tg is the tangent on the baseline starting from point B, with the differential peak scanning calorie maximum peak temperature (point A) and the temperature at −20 ° C. from the maximum peak temperature (point B) plotted on the differential scanning calorimetry curve. And the intersection of the tangent starting from point A.

(4) Transparency (measurement of total light transmittance)
The transparency was measured using a HAZE meter (“HGM-2DP” manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS-K7105 (Measurement Method A): 1981 for the total light transmittance of the test piece for transparency evaluation.

(5) Water absorption rate The water absorption rate was determined by immersing the film in water at 23 ° C. for 24 hours and calculating the mass change before and after immersion.

[Production Example 1]
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene (100 parts by mass), 1-hexene (4 parts by mass) as a molecular weight regulator, and toluene (200 parts by mass) as a solvent were charged into a nitrogen-substituted reaction vessel and heated to 80 ° C. To this, 0.12 parts by mass of a toluene solution of triethylaluminum (concentration 0.6 mol / L) and 0.37 parts by mass of a toluene solution of methanol-modified WCl ₆ (concentration 0.025 mol / L) were added and reacted at 80 ° C. for 1 hour. To obtain a polymer.

The obtained polymer solution was put into an autoclave, and further 200 parts by mass of toluene as a solvent and 0.06 parts by mass of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ as a hydrogenation catalyst were added, and then nitrogen was added. The substitution was performed 3 times. Next, hydrogen gas was charged into the reaction vessel, and the pressure was adjusted to 8.0 MPa. Then, after heating to 165 degreeC, reaction was performed at 165 degreeC for 3 hours, keeping the pressure at 10 MPa, and the hydrogenated body was obtained. The hydrogenated product was recovered by reprecipitation with methanol and then dried to obtain a polymer (A).

This (A) polymer has an intrinsic viscosity [η] = 0.78 dL / g, weight average molecular weight (Mw) = 11.5 × 10 ⁴ , molecular weight distribution (Mw / Mn) = 3.3, glass transition temperature ( Tg) = 167 ° C. Moreover, when the hydrogenation rate of (A) polymer was calculated | required by < ¹ > H-NMR measurement, the olefinic unsaturated bond in a principal chain was hydrogenated 99.9% or more.

[Production Example 2]
20 parts by mass of the dried cellulose was suspended in 440 parts by mass of N, N-dimethylacetamide and stirred at 160 ° C. for 1 hour. Thereafter, about 38 parts by mass of N, N-dimethylacetamide was removed from the suspension under reduced pressure in a nitrogen atmosphere, then cooled to 100 ° C., 40 parts by mass of lithium chloride was added, and further cooled to room temperature while stirring. Thus, cellulose was dissolved over 3 hours.

  After adding 86 parts by mass of a 50% by mass N, N-dimethylacetamide solution of triethylamine to this cellulose solution and further stirring, 60% by mass of a 50% by mass dimethylacetamide solution of p-toluenesulfonic acid chloride while maintaining the reaction solution at 5 ° C. The portion was added gradually over 30 minutes. Then, it stirred at 5 degreeC for 24 hours.

To the reaction solution, 81 parts by mass of octanoyl chloride was further added and stirred at room temperature for 8 hours. The reaction solution is gradually poured into 5,000 parts by mass of ice water, and further washed with 3,000 parts by mass of water and ethanol, respectively, and then suspended in 1,000 parts by mass of acetone. The reaction was precipitated by pouring into water. The precipitate was filtered, washed with ethanol and vacuum dried at 50 ° C. for 48 hours to obtain tosyloctanoyl cellulose. The degree of substitution of the obtained tosyloctanoyl cellulose was determined from ¹ H-NMR, and the tosyl group was 1.3, the octanoyl group was 1.7, and the total degree of substitution was 3.0.

  After suspending 3.5 parts by mass of the obtained tosyloctanoyl cellulose in 330 parts by mass of N, N-dimethylformamide, 3.5 parts by mass of sodium 4-hydroxyphenylacetate was added, and the reaction was performed at 100 ° C. under a nitrogen atmosphere. Heated for 3 hours.

N, N-dimethylformamide was removed from the reaction solution under reduced pressure, and the residue was washed with water / methanol and then vacuum dried at 50 ° C. for 48 hours to obtain (B) modified cellulose. The degree of substitution of the obtained (B) modified cellulose was determined from ¹ H-NMR, and the tosyl group was 0.8, the octanoyl group was 1.7, the (4-hydroxyphenyl) acetyl group was 0.5, and the total degree of substitution. Was 3.0.

[Example 1]
(A) 5 parts by mass of the polymer obtained in Production Example 1 and (B) 5 parts by mass of the modified cellulose obtained in Production Example 2 were dissolved in 200 parts by mass of methylene chloride, and then poured into a glass petri dish and naturally dried. Then, the film was vacuum-dried at room temperature for 48 hours and at 80 ° C. for 48 hours to obtain a transparent film having a thickness of 200 μm. When the total light transmittance of the obtained film was measured, it was 92% and the water absorption was 1.1%.

[Example 2]
When a film was prepared by changing the modified cellulose (B) in Example 1 to triacetyl cellulose, the total light transmittance was 85% and the water absorption was 2.0%.

[Comparative Example 1]
When a film was prepared by changing the modified cellulose (B) in Example 1 to cellulose, a non-uniform film was obtained. The total light transmittance was 52%, and the water absorption was 30%.

  As is clear from the above results, the use of (B) modified cellulose together with (A) polymer results in lower total light transmittance (higher transparency) and water absorption than when other celluloses are used. An optical film having a low rate (excellent water resistance) was obtained.

  In the resin composition of the present invention, the modified cellulose having a specific structural unit is suitably compatibilized with a polymer having a structural unit derived from a cyclic olefin in the main chain. Since the optical film of the present invention is formed using a resin composition in which polymers are suitably compatible with each other, the white turbidity of the film is suppressed and the light transmittance is high. In addition, the resin composition contains the polymer and the specific modified cellulose, so that a sufficient phase difference is developed and water absorption can be lowered, so that optical distortion due to environmental changes such as high temperature and high humidity can be reduced. Generation can be suppressed. In addition, since the optical film is a polymer that is compatible with each other, the viewing angle is reduced due to insufficient lamination accuracy, heat unevenness, etc., compared to the case where each polymer is individually filmed and laminated. It is possible to reduce the cost and reduce the cost.

Claims (4)

A resin composition comprising a polymer having a first structural unit derived from a cyclic olefin in the main chain and a modified cellulose having a second structural unit represented by the following formula (1).

(In the formula (1), R ¹ to R ³ are each independently a hydrogen atom or a monovalent substituent. Above Symbol substituent, an oxygen atom, a sulfur atom, including the nitrogen atom or a silicon atom And at least one selected from the group consisting of an acyl group having 2 to 20 carbon atoms and an organic sulfonyl group having 2 to 20 carbon atoms, provided that at least one of R ^{1 to} R ³ is (It is the said substituent containing the monovalent group represented by following formula (4). The total substitution degree by the said substituent in the said 2nd structural unit is 1-3 .)

(In Formula (4), Z an oxygen atom, a sulfur ^{atom, -O-R 8 -O -,} - S-R 8 -S-, or ^{-O-R 8} .R 8 is -S- is (This is a divalent linking group having 1 to 4 carbon atoms.) The resin composition according to claim 1, wherein the first structural unit is represented by the following formula (2).

(In formula (2), R ^{4 to} R ⁷ are each independently the following (i) to (vi), provided that R ^{4 to} R ⁷ are the following (vii) or (viii): P and m are each independently an integer of 0 to 3.)
(I) a hydrogen atom (ii) a halogen atom (iii) a trialkylsilyl group (iv) a substituted or unsubstituted 1-30 hydrocarbon group having a linking group containing an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom ( v) A substituted or unsubstituted 1-30 hydrocarbon group (excluding (iv))
(Vi) Polar group (excluding (iv) and (v))
(Vii) An alkylidene group formed by combining R ⁴ and R ⁵ with each other or R ⁶ and R ⁷ with each other. (However, R ⁴ and R ⁵ , or R ⁶ and R ⁷ , which are not involved in the mutual bond, are each independently any atom or group of (i) to (vi) above)
(Viii) At least two of R ^{4 to} R ⁷ are bonded to each other to form a monocyclic or polycyclic hydrocarbon ring or heterocyclic ring together with the carbon to which they are bonded. (However, R ^{4 to} R ⁷ , which are not involved in the mutual bond among R ^{4 to} R ⁷ , are each independently any atom or group of (i) to (vi) above).   3. The resin composition according to claim 1, wherein the total light transmittance is 90% or more when the film is 200 μm thick.   An optical film formed from the resin composition according to claim 1, claim 2 or claim 3.