TWI794524B - Optical film, optical stack and liquid crystal display device - Google Patents

Abstract

An optical film, which is an optical film made of thermoplastic northylene resin, and is a stretched film, the stress birefringence C _R of the thermoplastic northylene resin is greater than 2900×10 ⁻¹² Pa ⁻¹ , and the glass transition temperature Tg is 125° C. or higher, and the ratio (Rth/d) of the retardation Rth in the thickness direction of the optical film to the thickness d is 3.5×10 ⁻³ or higher. An optical stack with the optical film and a liquid crystal display device with the optical stack are also provided.

Description

Optical film, optical stack and liquid crystal display device

The invention relates to an optical film, an optical stack and a liquid crystal display device.

Conventionally, optical films made of thermoplastic resins are known. For example, Patent Document 1 has disclosed an optical film including a thermoplastic northylene resin.

"Patent Documents" "Patent Document 1": Japanese Patent Laid-Open No. 2003-238705 (corresponding gazette: US Patent Application Laid-Open No. 2004/057141 specification)

An optical film used in a liquid crystal display device has been demanded to have excellent phase difference exhibitability and a high retardation Rth in the thickness direction. As a method of obtaining an optical film having a high retardation Rth in the thickness direction using a conventional thermoplastic resin film, stretching at a high stretching ratio can be considered. However, when a film obtained by stretching at a high stretching ratio is joined to another member, the film may be peeled off from the other member (delamination) due to damage to the portion adjacent to the surface of the film.

The present invention was made in view of the foregoing problems, and an object of the present invention is to provide an optical film having excellent retardation in the thickness direction and suppressing delamination, an optical stack having the optical film, and an optical stack having the same. Body liquid crystal display device.

The inventors of the present invention have devoted themselves to research in order to solve the aforementioned problems. As a result, the present inventors found that by using a thermoplastic northylene resin having a large stress birefringence _CR and a high glass transition temperature Tg as the material of the optical film, the retardation Rth in the thickness direction of the optical film is compared with the thickness d The ratio (Rth/d) of the above-mentioned problem can be solved by making the ratio (Rth/d) more than the specified value, and the present invention has been completed.

That is, the present invention includes the following.

[1] An optical film, which is an optical film made of a thermoplastic northylene-based resin, and is a stretched film, wherein the stress birefringence C _R of the thermoplastic northylene-based resin is greater than 2900×10 ⁻¹² Pa ⁻¹ , the glass transition temperature Tg is 125°C or higher, and the ratio (Rth/d) of the retardation Rth in the thickness direction of the optical film to the thickness d (Rth/d) is 3.5×10 ⁻³ or higher.

[2] The optical film as described in [1], wherein the retardation Re in the in-plane direction is 40 nm or more and 80 nm or less.

[3] The optical film as described in [1] or [2], wherein The aforementioned thermoplastic northylene-based resin comprises a polymer, The foregoing polymer comprises a northylene-based monomer unit having an aromatic ring structure.

[4] The optical film according to [3], wherein the polymer contains 25% by weight or more of the northylene-based monomer unit having an aromatic ring structure.

[5] An optical stack comprising: The optical film described in any one of [1] to [4], and A polarizing plate arranged on the aforementioned optical film.

[6] A liquid crystal display device comprising the optical stack as described in [5].

According to the present invention, it is possible to provide an optical film having excellent retardation, high retardation in the thickness direction, and suppressed delamination, an optical stack including the optical film, and a liquid crystal display device including the optical stack.

Embodiments and examples are disclosed below to describe the present invention in detail. However, the present invention is not limited to the implementation forms and examples shown below, and can be implemented with arbitrary changes within the scope not departing from the scope of the patent application and its equivalent scope of the present invention.

In the following description, unless otherwise noted, the in-plane retardation Re of the film is represented by Re=(nx-ny)×d. In addition, the retardation Rth in the thickness direction of the film is a value represented by Rth={[(nx+ny)/2]-nz}×d unless otherwise noted. Here, nx represents the refractive index which is the direction (in-plane direction) perpendicular to the thickness direction of a film and the direction which gives a maximum refractive index. ny represents the refractive index in the direction which is the aforementioned in-plane direction and is perpendicular to the direction of nx. nz represents the refractive index in the thickness direction. d represents the thickness of the film. Measurement wavelength is 550 nm unless otherwise noted.

In the following description, the direction of the so-called constituent elements is "parallel", "perpendicular" or "orthogonal". Unless otherwise noted, it can also be included within the range that does not impair the effect of the present invention, for example, usually ±5 °──preferably ±2°, preferably ±1°──the error within the range.

In the following description, the MD direction (machine direction) is the flow direction of the film in the production line, and the TD direction (traverse direction) is the direction parallel to the film surface and perpendicular to the MD direction. In addition, in terms of cost, the long side direction of a strip-shaped film may be referred to as the MD direction of the film, and the width direction may be referred to as the TD direction of the film.

In the following description, the so-called "long strip" film refers to a film that has a length of 5 times or more, preferably 10 times or more, with respect to the width of the film, and specifically refers to a film that can be rolled. The length to be stored or transported in a roll shape. The upper limit of the ratio of the length of the film to the width is not particularly limited, but may be set at, for example, 100,000 times or less.

In the following description, the term "polarizing plate" includes not only rigid members but also flexible members such as resin films, unless otherwise noted.

[1. Optical film]

The optical film of the present invention is a film made of thermoplastic northylene-based resin. The optical film is a stretched film obtained by stretching a film which is a material of the optical film. In the following description, a film to be a material of an optical film is also referred to as a "film before stretching".

(thermoplastic northylene resin)

The thermoplastic northylene-based resin includes a polymer. Examples of the polymer contained in the thermoplastic northylene-based resin include ring-opening polymers of monomers having a northylene structure, or ring-opening copolymers of monomers having a northylene structure and other monomers, Or these hydrides; addition polymers of monomers having a northylene structure, or addition copolymers of monomers having a northylene structure and other monomers, or these hydrides.

Examples of monomers having a northene structure include bicyclo[2.2.1]hept-2-ene (common name: northene), tricyclo[4.3.0.1 ^2,5 ]dec-3,7-diene (common name: dicyclopentadiene, also known as "DCPD"), tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ] dode-3-ene (common name: tetracyclododecene, also known as "DCPD") TCD"), and derivatives of these compounds (such as those with substituents on the ring). Here, as a substituent, an alkyl group, an alkylene group, a polar group etc. are mentioned, for example. In addition, these substituents may be the same or different and may be bonded to the ring in plural. The monomer having a northylene structure can be used alone or in combination of two or more.

As a kind of polar group, a hetero atom or an atomic group having a hetero atom, etc. are mentioned. 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 carboxyl group, carbonyloxycarbonyl group, epoxy group, hydroxyl group, oxy group, ester group, silanol group, silyl group, amine group, nitrile group, pyl group and the like. In order to obtain a thin film with a low saturated water absorption, it is better to have a small amount of polar groups, and it is more preferable to have no polar groups.

As a monomer having a nor-alkene structure, from the viewpoint of excellent phase difference development, a nor-alene-based monomer having an aromatic ring structure may be used instead of the above-mentioned monomer having a nor-alkene structure or in combination with the above-mentioned nor-alkene-based monomer. Alkene monomers are used together.

Examples of the northene-based monomer having an aromatic ring structure include: 5-phenyl-2-northene, 5-(4-methylphenyl)-2-northene, 5-(1-naphthalene Base)-2-nor-nor-ene, 9-(2-nor-en-5-yl)carbazole and other nor-nor-ene monomers with aromatic substituents; 1,4-methylbridge-1,4,4a ,4b,5,8,8a,9a-Octahydrofluorene, 1,4-Abridged-1,4,4a,9a-Tetrahydrofluorene (common name: Abridged Tetrahydrofluorene, hereinafter also referred to as "MTF") , 1,4-methylbridge-1,4,4a,9a-tetrahydrodibenzofuran, 1,4-methylbridge-1,4,4a,9a-tetrahydrocarbazole, 1,4-methylbridge- 1,4,4a,9,9a,10-hexahydroanthracene, 1,4-methylbridge-1,4,4a,9,10,10a-hexahydrophenanthrene are equal to the condensed polycyclic structure with nor-alkene ring Nor-alkene-based monomers with aromatic ring structures; etc. These monomers can be used individually by 1 type or in combination of 2 or more types.

The northylene-based monomer having an aromatic ring structure may also have a substituent. Examples of substituents include alkyl groups such as methyl, ethyl, propyl, and isopropyl; alkylene groups; alkenyl groups; halogen groups such as fluorine, chlorine, bromine, and iodine; hydroxyl; Alkoxy group; cyano group; amido group; amido group; silicon group; etc. The northylene-based monomer having an aromatic ring structure may have two or more of these substituents.

Other monomers capable of ring-opening copolymerization with monomers having a northylene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene, and their derivatives; cyclohexadiene, cyclohexene, and Cyclic conjugated dienes such as heptadiene and their derivatives; etc.

A ring-opening polymer of a monomer having a nor-alkene structure and a ring-opening copolymer of a monomer having a nor-alene structure and other monomers that can be copolymerized can be obtained by subjecting the monomer to a well-known ring-opening polymerization catalyst obtained by (co)polymerization in the presence of .

Examples of other monomers capable of addition copolymerization with monomers having a nor-alkene structure include: α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and their derivatives; Butene, cyclopentene, cyclohexene and other cyclic olefins and their derivatives; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4- Non-conjugated dienes such as hexadiene, etc. These monomers can be used individually by 1 type or in combination of 2 or more types. Among these, α-olefins are preferred, and ethylene is preferred.

Addition polymers of monomers having a northylene structure and addition copolymers of monomers having a northylene structure and other monomers capable of copolymerization can be obtained by subjecting the monomers to well-known addition polymerization catalysts obtained by polymerization in the presence of .

The hydrogenated product of the ring-opening polymer of a monomer having a nor-alene structure, the hydrogenated product of a ring-opening copolymer of a monomer having a nor-alene structure and other monomers capable of ring-opening copolymerization with it, and a hydrogenated product of a ring-opening copolymer having a nor-alene The hydrogenated product of the addition polymer of the monomer of the structure, and the hydrogenated product of the addition copolymer of the monomer having the nor-alkene structure and other monomers that can be added and copolymerized with it, can be obtained by such ring opening It is obtained by adding a well-known hydrogenation catalyst containing transition metals such as nickel and palladium to a solution of a (co)polymer or an addition (co)polymer, bringing it into contact with hydrogen, and hydrogenating a carbon-carbon unsaturated bond.

In the present invention, the polymer is a ring-opened (co)polymer in which non-aromatic unsaturated bonds are selectively hydrogenated and includes a polymer having an aromatic ring structure from the viewpoint of excellent phase difference development. 𦯉Ethylene-based monomer units are preferred. Here, the "monomer unit" refers to a structural unit having a structure formed by polymerizing its monomer.

A polymer comprising a northylene-based monomer unit having an aromatic ring structure can be obtained by adding a ruthenium catalyst to a solution of the above-mentioned ring-opening (co)polymer or addition (co)polymer and exposing it to hydrogen. Examples of ruthenium catalysts include: [1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene](tricyclohexylphosphine)benzylidene ruthenium dichloride, hydrochloride Carbonyl ginseng (triphenylphosphine) ruthenium, bis (tricyclohexyl phosphine) benzylidene ruthenium(IV) dichloride, dichloro ginseng (triphenylphosphine) ruthenium, di )ruthenium. By analyzing the product obtained as a result of such hydrogenation by ¹ H-NMR, the presence or absence of carbon-carbon double bonds in the main chain structure can be distinguished from unsaturated bonds in the aromatic ring structure. Therefore, by such an analysis by ¹ H-NMR, it can be confirmed whether non-aromatic unsaturated bonds are selectively hydrogenated.

In the case where the polymer contains a northylene-based monomer unit having an aromatic ring structure, the amount of the northylene-based monomer unit having an aromatic ring structure in the polymer is preferably at least 25% by weight, preferably at least 40% by weight It is more preferable, and it is preferably below 80% by weight, preferably below 60% by weight. If the amount of the northylene-based monomer unit having an aromatic ring structure in the polymer is above the lower limit, the stress birefringence _CR can be increased, and the elongation ratio of the film before stretching can be suppressed, and at the same time, the optical film can be improved. Rth.

The molecular weight of the polymer contained in the thermoplastic northylene-based resin can be appropriately selected according to the purpose of use of the optical film, but the gel permeation layer can be obtained by using cyclohexane (toluene if the resin is insoluble) as a solvent. In terms of weight average molecular weight (Mw) converted from polyisoprene (polystyrene when the solvent is toluene) measured by analysis method, it is preferably 10,000-100,000, preferably 15,000-80,000, and 20,000-60,000 For Yu Jia. When the weight average molecular weight is in such a range, the mechanical strength and formability of the film are highly balanced, so it is suitable.

The molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of the polymer contained in the thermoplastic northylene resin is not particularly limited, but it is usually 1.0 to 10.0—preferably 1.0 to 5.0, The range of 1.0 to 3.5 is preferable.

The thermoplastic northylene-based resin may contain optional components other than polymers. Examples of optional components include ultraviolet absorbers, antioxidants, heat stabilizers, light stabilizers, antistatic agents, dispersants, chlorine scavengers, flame retardants, crystal nucleating agents, strengthening agents, anticaking agents, Anti-fog agent, release agent, pigment, organic or inorganic filler, neutralizer, slip agent, decomposer, metal deactivator, antifouling agent and antibacterial agent.

Examples of ultraviolet absorbers include: oxybenzophenone-based compounds, benzotriazole-based compounds, salicylate-based compounds, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, Acrylonitrile-based UV absorbers, trioxane-based compounds, nickel-zirconia salt-based compounds, and inorganic powders. Examples of suitable UV absorbers include: 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2 -yl)phenol], 2-(2'-hydroxy-3'-tertiary butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2,4-bis(tertiary butyl) -6-(5-chlorobenzotriazol-2-yl)phenol, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'- Tetrahydroxybenzophenone. Particularly suitable examples include: 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl )phenol].

When the thermoplastic northylene-based resin contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.5 to 5% by weight per 100% by weight of the thermoplastic northene resin.

(Physical properties of thermoplastic northylene-based resins)

In the present invention, the stress birefringence C _R of the thermoplastic northylene-based resin is larger than 2900×10 ⁻¹² Pa ⁻¹ . The stress birefringence C _R of thermoplastic northylene-based resins is preferably above 2910×10 ⁻¹² Pa ⁻¹ , more preferably above 3000×10 ⁻¹² Pa ⁻¹ , and below 8000×10 ⁻¹² Pa ⁻¹ Preferably, below 6000×10 ⁻¹² Pa ⁻¹ is better. By making the stress birefringence C _R of the thermoplastic northylene resin larger than 2900×10 ⁻¹² Pa ⁻¹ , the stretching ratio when stretching the film before stretching can be suppressed, and the Rth of the optical film can be increased at the same time. By making the stress birefringence C _R of the thermoplastic northylene-based resin below the upper limit, Re and Rth of the film can be easily controlled, and in-plane variation can be suppressed.

Stress birefringence C _R can be controlled by changing the proportion of monomers used in the manufacture of polymers contained in thermoplastic northylene-based resins. For example, if the ratio of the above-mentioned northylene-based monomer having an aromatic ring structure is increased, the stress birefringence _CR can be increased.

Stress birefringence C _R can be measured by, for example, the following method.

A sample is made by molding a thermoplastic northylene-based resin into a sheet. After fixing both ends of the sample with clamps, a weight of a specified weight (for example, 160 g) is fixed to one of the clamps. Then, in an oven set at a specified temperature (such as the glass transition temperature (Tg) of the resin + 5°C), set the jig with the unfixed weight as a support point, and hang the sheet for a specified time (such as 1 hour) for stretching. . Slowly cool the stretched sample sheet back to room temperature, and use it as a measurement sample. For this measurement sample, the retardation value (a nm) and the thickness (b mm) of the measurement sample center portion of the measurement sample were measured using a birefringence meter. Using these measured values (a, b), the δn value was calculated by the following formula (1). δn=a×(1/b)×10 ⁻⁶ (1)

Using this δn value and the stress applied to the sample (in the above case, the stress applied when the specified weight is fixed), _CR can be calculated by the following formula (2). C _R =δn/stress (2)

The glass transition temperature Tg of thermoplastic northylene resin is above 125°C. The glass transition temperature Tg is preferably above 130°C, more preferably above 135°C, preferably below 180°C, more preferably below 160°C. By making the glass transition temperature Tg higher than 125°C, it is possible to produce an optical film having excellent heat resistance and durability. Tg has to be measured using a differential scanning calorimeter.

(film before stretching)

The pre-stretched film used as the material of the optical film is a film made of the above-mentioned thermoplastic northylene-based resin.

The film before stretching is produced by forming a thermoplastic northylene-based resin into a film by a well-known method such as casting, extrusion, inflation, and the like.

(optical film)

An optical film can be obtained by stretching a film before stretching. The stretching conditions when stretching the pre-stretching film into an optical film are properly selected so as to obtain desired optical properties. For example, the stretching mode when stretching a pre-stretching film into an optical film may be any mode such as uniaxial stretching, biaxial stretching (simultaneous biaxial stretching, sequential biaxial stretching). Among these aspects, biaxial stretching is preferred. And, in the case where the film before stretching is a long film, the direction of stretching is longitudinal (direction parallel to the long side direction of the long film), transverse direction (direction parallel to the width direction of the long film) and Any oblique direction (a direction that is neither vertical nor horizontal) is acceptable.

When the film before stretching is stretched to form an optical film, the stretching ratio is preferably at least 1.4, more preferably at least 1.5, and preferably at most 2.2, more preferably at most 2.1. If the elongation ratio is made below the upper limit of the above-mentioned range, the occurrence of delamination can be more effectively suppressed, and if the elongation ratio is made above the lower limit of the above-mentioned range, Rth can be increased. When stretching the film before stretching by biaxial stretching in the MD direction and the TD direction, it is preferable that the product of the stretching ratio in the MD direction and the stretching ratio in the TD direction be in the above-mentioned range.

When stretching the pre-stretched film to make an optical film, the stretching temperature is preferably above Tg°C, preferably above (Tg+5)°C, on the other hand, preferably below (Tg+40)°C, preferably below (Tg+30)°C better. When the stretching temperature is within the aforementioned range, an optical film with uniform film thickness can be obtained.

(Physical property value of optical film)

The thickness d of the optical film is preferably 30 μm or more, more preferably 40 μm or more, and preferably 150 μm or less, more preferably 100 μm or less. By setting the thickness of the optical film above the lower limit, the occurrence of delamination can be effectively suppressed, and by making the thickness of the optical film below the upper limit, it is possible to reduce the thickness of the device incorporating the optical film.

In the present invention, the ratio (Rth/d) of the retardation Rth in the thickness direction of the optical film to the thickness d is 3.5×10 ⁻³ or more. Rth/d is preferably above 3.5×10 ⁻³ , preferably above 4.0×10 ⁻³ , preferably below 8.0×10 ⁻³ , and preferably below 6.0×10 ⁻³ . By making Rth/d more than 3.5×10 ⁻³ , an optical film with high Rth and small thickness can be obtained, thereby obtaining a film with excellent optical compensation. By making Rth/d equal to or less than the upper limit, the occurrence of delamination can be more effectively suppressed.

The in-plane retardation Re of the optical film is preferably at least 40 nm, more preferably at least 50 nm, and preferably at most 80 nm, more preferably at most 70 nm. By making Re equal to or greater than the lower limit, the phase difference display can be optimized, and by making Re equal to or less than the upper limit, in-plane variation can be suppressed. Retardation Re is properly selected within the above range to suit the design of the display device.

(optical stack)

The optical stack of the present invention includes the optical film of the present invention and a polarizing plate disposed thereon.

As a polarizing plate, it can be used on one or both sides of a polarizer made of a polyvinyl alcohol-based polarizing film containing a dichroic substance, for example, a film that becomes a protective layer (protective film) is bonded to an intermediary bonding layer .

As the polarizer (polarizing film), for example, a dichroic substance such as iodine or a dichroic dye is applied to a film made of vinyl alcohol-based polymers such as polyvinyl alcohol or partially formalized polyvinyl alcohol. Dyeing treatment, stretching treatment, cross-linking treatment and other processors. As the polarizer, it is necessary to use one that penetrates linearly polarized light when natural light is incident on it.

A transparent film can be used as a protective film material to be a transparent protective layer provided on one or both sides of a polarizer (polarizing film). As the transparent film, it is preferable to use a film made of a resin excellent in transparency, mechanical strength, thermal stability, moisture shielding property, and the like. Examples of such resins include acetate-based resins such as cellulose triacetate or polyester-based resins, polyether-based resins, polycarbonate-based resins, polyamide-based resins, and polyimide-based resins. Resin, polyolefin resin, norolefin resin, acrylic resin, etc. From the viewpoint of small birefringence, acetate-based resins or northylene-based resins are preferable, and from the viewpoints of transparency, low hygroscopicity, dimensional stability, and light weight, norbthylene-based resins are preferred. Resin is especially preferred.

The thickness of the protective film is arbitrary, but it is generally 500 μm or less, preferably 5-300 μm, particularly preferably 5-150 μm, for the purpose of thinning the polarizing plate.

The stacking of the optical film and the polarizing plate is carried out by laminating the bonded layers through an intermediary. As an example of such a layer body, the layer body of an adhesive agent, and the layer body of an adhesive agent are mentioned. Examples of adhesives or adhesives include acrylic, silicone, polyester, polyurethane, polyether, and rubber. Among them, acrylic-based ones are preferable from the viewpoint of heat resistance, transparency, and the like.

In the optical stacked body of the present invention, the optical film of the present invention can also serve as a protective film of the stacked polarizing plates, thereby making it possible to reduce the thickness of the components. In addition, the stacking of the optical film and the polarizing plate can be performed by roll-to-roll, so that a long optical stack can be obtained. The angle between the slow axis of the optical film in the optical stack and the absorption axis of the polarizer must be within the range of 90°±1°.

The thickness of the optical stack of the present invention is preferably above 30 μm, more preferably above 40 μm, preferably below 150 μm, preferably below 100 μm.

[Liquid crystal display device]

The liquid crystal display device of the present invention includes the optical stacked body of the present invention. The liquid crystal display device of the present invention includes the optical stacked body of the present invention on at least one side of a liquid crystal cell.

In a liquid crystal display device, the optical film is usually arranged between the liquid crystal unit of the liquid crystal display device and the viewing side polarizer. In this configuration, the optical film can function as a viewing angle compensation film.

Liquid crystal cells are used for example: in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-area vertical alignment (MVA) mode, continuous pyrotechnic alignment (CPA) mode, mixed alignment nematic (HAN) mode, twisted nematic (TN) mode, super twisted nematic (STN) mode, optically compensated bend (OCB) mode and other liquid crystal cells in any mode.

In the case where polarizers are provided on both sides of the liquid crystal cell, the polarizers may be the same or different.

In the liquid crystal display device of the present invention, an adhesive layer may be provided in order to bond the optical stack of the present invention to the liquid crystal cell. The adhesive layer can be appropriately formed using conventionally known adhesives such as acrylic. Among them, the prevention of foaming or peeling caused by moisture absorption, the reduction of optical properties caused by thermal expansion differences, or the warping of liquid crystal cells, and the formation of high-quality and durable liquid crystal display devices In terms of performance and other points, the adhesive layer with low moisture absorption rate and excellent heat resistance is preferable. In addition, it is necessary to form an adhesive layer or the like that contains fine particles and exhibits light diffusing properties.

"Example"

Examples are disclosed below to specifically illustrate the present invention. However, the present invention is not limited to the following examples, and can be implemented with arbitrary changes within the scope not departing from the scope of patent application and its equivalent scope of the present invention.

In the following descriptions, "%" and "parts" indicating amounts are based on weight unless otherwise noted. Unless otherwise noted, the following operations were carried out in the atmosphere at normal temperature and pressure.

[Measurement and calculation methods of physical properties of polymers]

(Measurement of weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw/Mn))

The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polymers (ring-opened polymers and polymers (1) to (3), polymers (C1) to (C5)) were determined by using cyclohexane Measured by gel permeation chromatography (GPC) as an eluent, and obtained as a standard polyisoprene conversion value.

As the standard polyisoprene, standard polyisoprene manufactured by Tosoh Corporation (Mw=602, 1390, 3920, 8050, 13800, 22700, 58800, 71300, 109000, 280000) was used.

The measurement was performed by using three Tosoh columns (TSKgel G5000HXL, TSKgel G4000HXL, and TSKgel G2000HXL) in series at a flow rate of 1.0 mL/min, a sample injection volume of 100 μL, and a column temperature of 40°C.

The molecular weight distribution (Mw/Mn) was calculated using the measured value measured by the above-mentioned method.

(Measurement of glass transition temperature (Tg))

The glass transition temperature (Tg) of polymers (1) to (3) and polymers (C1) to (C5) was based on JIS using a differential scanning calorimeter (manufactured by SII NanoTechnology Inc., product name: DSC6220) K 6911, measured at a heating rate of 10°C/min.

(measurement of stress birefringence C _R )

Polymers (1) to (3) and polymers (C1) to (C5) were respectively formed into thin sheets of 35 mm×10 mm×1 mm to prepare samples. After fixing both ends of the sample with clamps, a 160 g weight was fixed to one of the clamps. Subsequently, in an oven whose temperature has been set to the glass transition temperature (Tg) of the polymer + 5°C, set the jig without a fixed weight as a support point, hang the sheet for 1 hour for stretching, and then slowly cool down to At room temperature, use it as a measuring sample.

For the aforementioned measurement sample, a birefringence meter (manufactured by Photonic Lattice, Inc., WPA-100) was used to measure the retardation value of the central part of the measurement sample in light with a wavelength of 650 nm (this measurement value was defined as a nm.). And, measure the thickness of the center portion of the test sample (this measurement value is defined as b mm.).

Using the measured values a and b, the δn value was calculated by the following formula (1). δn=a×(1/b)×10 ⁻⁶ (1)

Using this δn value and the stress applied to the sample, _CR was calculated by the following formula (2). C _R =δn/stress (2)

(Confirmation of the presence or absence of aromatic rings in hydrogenated nor-alene-based ring-opening copolymers)

The polymer before hydrogenation and the hydrogenated polymer were analyzed by ¹ H-NMR. In the analysis, deuterated chloroform was used as the solvent. From the analysis results, the hydrogenation rate of non-aromatic unsaturated bonds and the hydrogenation rate of aromatic unsaturated bonds were calculated. From these results, the presence or absence of the aromatic ring in the hydrogenated product of the northylene-based ring-opening copolymer was confirmed.

[Production Example 1: Production of Polymer (1)]

(1-1) Production of ring-opened polymers

In a glass reaction vessel replaced by nitrogen gas inside, add [1,3-di(2,4,6-trimethylphenyl)imidazolidine-2-ylidene dichloride](tricyclohexyl Phosphine) 0.05 parts by weight of benzylidene ruthenium, 500 parts by weight of toluene, 50 parts by weight of 1,4-methylbridge-1,4,4a,9a-tetrahydrofluorene (MTF) as a monomer, tetracyclododecene ( 20 parts by weight of TCD), 30 parts by weight of dicyclopentadiene (DCPD), and 0.75 parts by weight of 1-hexene as a chain transfer agent were stirred at 60° C. for 2 hours to perform ring-opening polymerization. The Mw of the obtained ring-opened polymer was 3.3×10 ⁴ , and the molecular weight distribution (Mw/Mn) was 2.3. Also, the conversion rate of monomer to polymer was 100%.

(1-2) Production of polymer (1)

Subsequently, 300 parts of the reaction solution containing the ring-opened polymer obtained in (1-1) was transferred to an autoclave with a stirrer, and carbonyl ginseng (triphenylphosphine) ruthenium hydrochloride (hereinafter abbreviated as " Ruthenium catalyst.") 0.0043 parts, hydrogenation reaction was carried out at 4.5 MPa and 160°C for 4 hours.

After completion of the hydrogenation reaction, the obtained solution was poured into a large amount of isopropanol to precipitate the polymer (hydride). After filtering off the obtained polymer, it was dried with a vacuum dryer (220° C., 1 Torr) for 6 hours to obtain a polymer (1). Mw of polymer (1) was 4.3×10 ⁴ , and Mw/Mn was 2.5. Also, the Tg of the polymer (1) is 128°C, and the C _R is 3900×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that in the polymer (1), non-aromatic unsaturated bonds were selectively hydrogenated, while aromatic unsaturated bonds remained .

[Production Example 2: Production of Polymer (2)]

(2-1) Production of ring-opened polymers

In addition to setting the addition amount of monomers (MTF, TCD and DCPD) as 40 parts by weight of MTF, 35 parts by weight of TCD, and 25 parts by weight of DCPD in (1-1) of Manufacturing Example 1, the same procedure as in Manufacturing Example 1 ( 1-1) By the same operation, a ring-opened polymer was obtained. The Mw of the ring-opened polymer was 3.1×10 ⁴ , and the molecular weight distribution was 2.2. The conversion of monomer to polymer was 100%.

(2-2) Production of polymer (2)

Except that in (1-2) of Production Example 1, 300 parts of the reaction solution containing the ring-opened polymer obtained in (2-1) was used instead of 300 parts of the reaction solution containing the ring-opened polymer obtained in (1-1) Otherwise, the same operation as (1-2) was carried out to obtain polymer (2). Mw of the polymer (2) was 4.0×10 ⁴ , and Mw/Mn was 2.4. Polymer (2) has a Tg of 136°C and a C _R of 3200×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that in the polymer (2), non-aromatic unsaturated bonds were selectively hydrogenated while aromatic unsaturated bonds remained .

[Production Example 3: Production of Polymer (3)]

(3-1) Production of ring-opened polymers

In addition to setting the addition amount of the monomers (MTF, TCD and DCPD) as 25 parts by weight of MTF, 35 parts by weight of TCD, and 40 parts by weight of DCPD in (1-1) of Production Example 1, the same method as that of Production Example 1 ( 1-1) By the same operation, a ring-opened polymer was obtained. The Mw of the ring-opened polymer was 3.2×10 ⁴ , and the molecular weight distribution was 2.4. The conversion of monomer to polymer was 100%.

(3-2) Production of polymer (3)

Except that in (1-2) of Production Example 1, 300 parts of the reaction solution containing the ring-opened polymer obtained in (3-1) was used instead of 300 parts of the reaction solution containing the ring-opened polymer obtained in (1-1) Otherwise, the same operation as (1-2) was carried out to obtain polymer (3). The Mw of the polymer (3) was 4.2×10 ⁴ , and Mw/Mn was 2.6. Polymer (3) has a Tg of 128°C and a C _R of 3000×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that in the polymer (3), non-aromatic unsaturated bonds were selectively hydrogenated while aromatic unsaturated bonds remained .

[Production Example 4: Production of Polymer (C1)]

(4-1) Production of ring-opened polymers

Except that the addition amount of the monomers (MTF, TCD and DCPD) was determined as 22 parts by weight of MTF, 38 parts by weight of TCD, and 40 parts by weight of DCPD in Production Example 1 (1-1), the same operation was carried out to obtain the open ring polymer. The Mw of the ring-opened polymer was 3.2×10 ⁴ , and the molecular weight distribution was 2.3. The conversion of monomer to polymer was 100%.

(4-2) Production of polymer (C1)

Except that in (1-2) of Production Example 1, 300 parts of the reaction solution containing the ring-opened polymer obtained in (4-1) was used instead of 300 parts of the reaction solution containing the ring-opened polymer obtained in (1-1) Otherwise, the same operation as (1-2) was carried out to obtain a polymer (C1). Mw of the polymer (C1) was 4.1×10 ⁴ , and Mw/Mn was 2.5. Polymer (C1) has a Tg of 129 °C and a _CR of 2850×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that in the polymer (C1), non-aromatic unsaturated bonds were selectively hydrogenated, while aromatic unsaturated bonds remained .

[Production Example 5: Production of Polymer (C2)]

(5-1) Production of ring-opened polymers

In addition to setting the addition amount of the monomers (MTF, TCD and DCPD) as 25 parts by weight of MTF, 35 parts by weight of TCD, and 40 parts by weight of DCPD in (1-1) of Production Example 1, the same method as that of Production Example 1 ( 1-1) By the same operation, a ring-opened polymer was obtained. The Mw of the ring-opened polymer was 3.2×10 ⁴ , and the molecular weight distribution was 2.4. The conversion of monomer to polymer was 100%.

(5-2) Production of polymer (C2)

Then, 300 parts of the reaction solution containing the ring-opened polymer obtained in (5-1) was transferred to an autoclave with a stirrer, and a diatomaceous earth-supported nickel catalyst (manufactured by Nikki Chemical Co., Ltd., product name "T8400RL") was added. , nickel loading rate 57%) 3 parts, the hydrogenation reaction was carried out at 4.5 MPa and 160°C for 4 hours.

After the hydrogenation reaction, the obtained solution was filtered with RADIOLITE #500 as a filter bed at a pressure of 0.25 MPa (manufactured by Ishikawajima Harima Heavy Industries Co., Ltd., product name "FUNDABAC filter") to remove the hydrogenation catalyst and obtain a colorless and transparent solution . The obtained solution was poured into a large amount of isopropanol to precipitate the polymer. After the obtained polymer was filtered off, it was dried with a vacuum dryer (220° C., 1 Torr) for 6 hours to obtain a polymer (C2). Mw of the polymer (C2) was 4.3×10 ⁴ , and Mw/Mn was 2.6. The polymer (C2) has a Tg of 136 °C and a _CR of 1900×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that both non-aromatic unsaturated bonds and aromatic unsaturated bonds were hydrogenated in the polymer (C2).

[Manufacture Example 6: Manufacture of Polymer (C3)]

(6-1) Production of ring-opened polymers

In addition to setting the addition amount of the monomers (MTF, TCD and DCPD) as 10 parts by weight of MTF, 40 parts by weight of TCD, and 50 parts by weight of DCPD in (1-1) of Production Example 1, the same method as that of Production Example 1 ( 1-1) By the same operation, a ring-opened polymer was obtained. The Mw of the ring-opened polymer was 3.2×10 ⁴ , and the molecular weight distribution was 2.3. The conversion of monomer to polymer was 100%.

(6-2) Production of polymer (C3)

Then, 300 parts of the reaction solution containing the ring-opened polymer obtained in (6-1) was transferred to an autoclave with a stirrer, and a diatomaceous earth-supported nickel catalyst (manufactured by Nikki Chemical Co., Ltd., product name "T8400RL") was added. , nickel loading rate 57%) 3 parts, the hydrogenation reaction was carried out at 4.5 MPa and 160°C for 4 hours.

After the hydrogenation reaction, the obtained solution was filtered with RADIOLITE #500 as a filter bed at a pressure of 0.25 MPa (manufactured by Ishikawajima Harima Heavy Industries Co., Ltd., product name "FUNDABAC filter") to remove the hydrogenation catalyst and obtain a colorless and transparent solution . The obtained solution was poured into a large amount of isopropanol to precipitate the polymer. After the obtained polymer was filtered off, it was dried with a vacuum dryer (220° C., 1 Torr) for 6 hours to obtain a polymer (C3). Mw of the polymer (C3) was 4.1×10 ⁴ , and Mw/Mn was 2.5. The polymer (C3) has a Tg of 128 °C and a C _R of 2200×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that both non-aromatic unsaturated bonds and aromatic unsaturated bonds were hydrogenated in the polymer (C3).

[Production Example 7: Production of Polymer (C4)]

(7-1) Production of ring-opened polymers

In addition to setting the addition amount of monomers (MTF, TCD and DCPD) as 5 parts by weight of MTF, 5 parts by weight of TCD, and 90 parts by weight of DCPD in (1-1) of Production Example 1, the same procedure as in (1-1) of Production Example 1 was carried out. 1-1) By the same operation, a ring-opened polymer was obtained. The Mw of the ring-opened polymer was 3.3×10 ⁴ , and the molecular weight distribution was 2.3. The conversion of monomer to polymer was 100%.

(7-2) Production of polymer (C4)

Then, 300 parts of the reaction solution containing the ring-opened polymer obtained in (7-1) was transferred to an autoclave with a stirrer, and a diatomaceous earth-supported nickel catalyst (manufactured by Nikki Chemical Co., Ltd., product name "T8400RL") was added. , nickel loading rate 57%) 3 parts, the hydrogenation reaction was carried out at 4.5 MPa and 160°C for 4 hours.

After the hydrogenation reaction, the obtained solution was filtered with RADIOLITE #500 as a filter bed at a pressure of 0.25 MPa (manufactured by Ishikawajima Harima Heavy Industries Co., Ltd., product name "FUNDABAC filter") to remove the hydrogenation catalyst and obtain a colorless and transparent solution . The obtained solution was poured into a large amount of isopropanol to precipitate the polymer. After the obtained polymer was filtered off, it was dried with a vacuum dryer (220° C., 1 Torr) for 6 hours to obtain a polymer (C4). Mw of the polymer (C4) was 3.9×10 ⁴ , and Mw/Mn was 2.7. The polymer (C4) has a Tg of 102°C and a C _R of 3100×10 ⁻¹² Pa ⁻¹ .

As a result of ¹ H-NMR analysis of the obtained polymer, it was confirmed that both non-aromatic unsaturated bonds and aromatic unsaturated bonds were hydrogenated in the polymer (C4).

[Production Example 8: Production of Polymer (C5)]

(8-1) Production of ring-opened polymers

In addition to using 50 parts by weight of TCD and 50 parts by weight of 8-methyltetracyclododecene (hereinafter sometimes abbreviated as MTD) in Production Example 1 (1-1) instead of MTF, TCD and DCPD as monomers, the A ring-opened polymer was obtained in the same manner as in (1-1) of Production Example 1. The Mw of the ring-opened polymer was 4.0×10 ⁴ , and the molecular weight distribution was 2.0. The conversion of monomer to polymer was 100%.

(8-2) Production of polymer (C5)

Subsequently, 300 parts of the polymerization reaction solution obtained in (8-1) was transferred to an autoclave with a stirrer, and a diatomaceous earth-supported nickel catalyst (manufactured by Nikki Chemical Co., Ltd., product name "T8400RL" with a nickel loading rate of 57 %) 3 parts, the hydrogenation reaction was carried out at a hydrogen pressure of 4.5 MPa and 160°C for 4 hours.

After the hydrogenation reaction, the obtained solution was filtered with RADIOLITE #500 as a filter bed at a pressure of 0.25 MPa (manufactured by Ishikawajima Harima Heavy Industries Co., Ltd., product name "FUNDABAC filter") to remove the hydrogenation catalyst and obtain a colorless and transparent solution . The obtained solution was poured into a large amount of isopropanol to precipitate the polymer. After filtering off the obtained polymer, it was dried with a vacuum dryer (220°C, 1 Torr) for 6 hours to obtain a polymer. The polymer had a Tg of 158°C.

28 parts by weight of this polymer, 10 parts by weight of maleic anhydride, and 3 parts by weight of dicumyl peroxide were dissolved in 130 parts by weight of tertiary butylbenzene, and reacted at 140° C. for 6 hours. The reaction product solution was poured into methanol to aggregate the reaction product. The aggregate was dried in a vacuum dryer (220° C., 1 Torr) for 6 hours to obtain a hydrogenated maleic acid-modified ring-opened polymer (polymer (C5)). Mw of the polymer (C5) was 5.6×10 ⁴ , and Mw/Mn was 2.5. The polymer (C5) has a Tg of 170°C, a C _R of 2000×10 ⁻¹² Pa ⁻¹ , and a maleic acid group content of 25 mol%.

[Evaluation method]

(Measurement of Rth, Re, d of stretched film and calculation of Rth/d)

The retardation Rth in the thickness direction and the retardation Re in the in-plane direction of the stretched films respectively obtained in Examples and Comparative Examples were measured at a measurement wavelength of 550 nm using a retardation meter ("AXOSCAN" manufactured by AXOMETRICS Corporation). The thickness d of the stretched film obtained in Examples and Comparative Examples was measured with a caliper ID-C112BS (manufactured by Mitutoyo Corporation).

Divide the measured Rth value by the thickness d of the stretched film to calculate Rth/d, and evaluate according to the following evaluation criteria. The results are shown in Table 1 and Table 2. In Table 1 and Table 2, Rth/d is described in the upper row, and the evaluation results are described in parentheses in the lower row. Good: more than 3.5×10 ⁻³ Bad: less than 3.5×10 ⁻³

(orientation angle accuracy)

The orientation angles θ of the stretched films obtained in Examples and Comparative Examples were measured using a polarizing microscope (manufactured by Olympus, polarizing microscope "BX51"), and the absolute values were calculated as orientation angles. The orientation angle θ was measured at an interval of 50 mm relative to the width direction of the stretched film and an interval of 10 m relative to the longitudinal direction. Calculate the standard deviation of these measurement results and define it as the orientation angle accuracy θσ. The results are shown in Table 1 and Table 2. It is better if the accuracy of orientation angle is small and the variation of orientation angle is small.

(Evaluation method for delamination)

<Measuring method of peel strength>

A resin film (Zeonor Film, glass transition temperature 160° C., thickness 100 μm, manufactured by Zeonor Co., Ltd., not particularly subjected to stretching treatment) made of a northylene-based polymer was prepared as an adherend. Corona treatment was applied to one side of the film to be measured (the stretched film obtained in Examples and Comparative Examples) and one side of the adherend. Adhesive is attached to both the corona-treated surface of the film to be measured and the corona-treated surface of the adherend, and the adhesive-adhered surfaces are bonded together. At this time, as the bonding agent, UV bonding agent CRB series (manufactured by TOYOCHEM CO., LTD.) was used. Afterwards, using an electrodeless UV irradiation device (manufactured by Heraeus), using a D bulb as a light source, UV irradiation was performed under the conditions of a peak illuminance of 100 mW/cm ² and an integrated light intensity of 3000 mJ/cm ² to cure the bonding agent . Thereby, a sample film including a film to be measured and an adherend is obtained.

A 90-degree peel test was performed on the obtained sample film. That is, the sample film is cut into a width of 15 mm, and the film side of the measurement object is attached to the surface of the glass slide with an adhesive. At this time, a double-sided adhesive tape (manufactured by Nitto Denko Co., Ltd., model "CS9621") was used as an adhesive. Clamp the adherend at the end of a high-performance digital force gauge ZP-5N (manufactured by IMADA), pull the adherend along the normal direction of the surface of the slide glass at a speed of 300 mm/min, and measure the traction The magnitude of the force is taken as the peel strength. The evaluation of the peel strength was performed according to the following evaluation criteria, and the results are shown in Table 1 and Table 2. In Table 1 and Table 2, measured values are described in the upper row, and evaluation results are described in parentheses in the lower row. Good: 1.0 N/15 mm or more Bad: Less than 1.0 N/15 mm

<Reference example: Evaluation of the validity of the peel strength measurement method>

An experiment was carried out to evaluate whether it can be said that "the measurement of the peel strength by the above-mentioned measuring method reflects the evaluator of the peel strength in the case of the adhered polarizer".

A polarizing film and an adhesive were prepared by the same method as that described in Example 1 of Japanese Patent Laid-Open No. 2005-70140. Furthermore, the stretched film obtained in Example 1 of the present application was prepared as a film to be measured. Corona treatment is applied to one side of the film to be measured, and this side is bonded to one of the surfaces of the polarizing film with an intermediary adhesive. On the other surface of the polarizing film, a cellulose triacetate film is pasted with an intermediary adhesive. Thereafter, it was dried at 80° C. for 7 minutes to cure the adhesive to obtain a sample film. For the obtained sample film, the same 90-degree peel test as in the above-mentioned <Measurement Method of Peel Strength> was carried out. As a result, a value of peel strength similar to that obtained in Example 1 of the present application was obtained. From this fact, it can be said that the measurement of the peel strength using the above-mentioned measurement method reflects the evaluation of the peel strength in the case of the adhered polarizer.

(Rth change rate after 500 hours at 85°C)

The stretched films of the examples and comparative examples were subjected to a durability test at 85°C for 500 hours, and the Rth of the stretched films before and after the test was measured, and the rate of change was calculated by the following formula, and evaluated by the following criteria. The smaller the change rate, the higher the heat resistance, and the better. In Table 1 and Table 2, the rate of change is described in the upper row, and the evaluation results are described in parentheses in the lower row. Rate of change (%) = (Rth before the test - Rth after the test) / Rth before the test × 100 Good: change rate is less than 3% Bad: the change rate is greater than 3%

(60°C, 90% humidity, Rth change rate after 500 hours)

For the stretched films of the examples and comparative examples, a durability test was carried out at 60°C, 90% humidity, and 500 hours, and the Rth of the stretched films before and after the test was measured, and the rate of change was calculated by the following formula, and by the following criteria to evaluate. The one with a small change rate is better in terms of heat resistance and moisture resistance. In Table 1 and Table 2, the rate of change is described in the upper row, and the evaluation results are described in parentheses in the lower row. Rate of change (%) = (Rth before the test - Rth after the test) / Rth before the test × 100 Good: change rate is less than 3% Bad: the change rate is greater than 3%

(measurement of water absorption)

A part of each stretched film of Examples and Comparative Examples was cut to prepare a test piece (size: 100 mm×100 mm), and the quality of the test piece was measured. Afterwards, the test piece was immersed in water at 23° C. for 24 hours, and the mass of the test piece after immersion was measured. Then, the ratio of the mass of the test piece increased by immersion to the mass of the test piece before immersion was calculated as water absorption (%). The smaller the water absorption rate, the better.

(Example 1)

(1-1) Production of film before stretching

The polymer (1) produced in Production Example 1 was put into a twin-screw extruder, and formed into a strand-shaped molded body by hot-melt extrusion. This molded body was finely cut with a strand cutter to obtain pellets of a resin containing the polymer (1).

After drying the pellets of the resin at 100° C. for 5 hours, the pellets were supplied to an extruder by a conventional method, melted at 250° C., and discharged from a die onto a cooling drum to obtain a film before stretching with a thickness of 110 μm.

(1-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.2 times in the longitudinal direction at 138° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and tenter chain tension are adjusted, and at the same time stretched 1.4 times in the transverse direction at a temperature of 138°C (Tg+10°C) to obtain biaxial stretching film. Re of the obtained biaxially stretched film was 60 nm, Rth was 320 nm, and thickness d was 65 μm. Table 1 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Example 2]

(2-1) Production of film before stretching

Except that polymer (2) produced in Production Example 2 was used instead of polymer (1) in (1-1) of Example 1, the same operation as (1-1) of Example 1 was carried out to obtain Object (2) is a film before stretching with a thickness of 118 μm.

(2-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.25 times in the longitudinal direction at 146°C (Tg+10°C) using a longitudinal stretcher using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.45 times in the transverse direction at a temperature of 146°C (Tg+10°C) to obtain biaxial stretching film. Re of the obtained biaxially stretched film was 60 nm, Rth was 310 nm, and thickness d was 65 μm. Table 1 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Example 3]

(3-1) Production of film before stretching

Except that the polymer (3) produced in Production Example 3 was used instead of the polymer (1) in (1-1) of Example 1, the same operation as (1-1) of Example 1 was carried out to obtain The unstretched film of the object (3) with a thickness of 127 μm.

(3-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.3 times in the longitudinal direction at 138° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.5 times in the transverse direction at a temperature of 138°C (Tg+10°C) to obtain biaxial stretching film. The Re of the obtained biaxially stretched film was 60 nm, the Rth was 300 nm, and the thickness d was 65 μm. Table 1 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 1]

(C1-1) Manufacture of film before stretching

Except that in (1-1) of Example 1, the polymer (C1) produced in Production Example 4 was used instead of the polymer (1) and the discharge amount of the molten resin was increased, the same procedure as in (1-1) of Example 1 was carried out. ) by the same operation to obtain a film before stretching with a thickness of 180 μm including the polymer (C1).

(C1-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.4 times in the longitudinal direction at 139° C. (Tg + 10° C.) using a longitudinal stretcher using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and tenter chain tension are adjusted, and at the same time stretched 1.6 times in the transverse direction at a temperature of 139°C (Tg+10°C) to obtain biaxial stretching film. The Re of the obtained biaxially stretched film was 60 nm, the Rth was 300 nm, and the thickness was 80 μm. Table 1 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 2]

(C2-1) Manufacture of film before stretching

Except that in (1-1) of Example 1, the polymer (C2) produced in Production Example 5 was used instead of the polymer (1) and the discharge amount of molten resin was increased, the same process as in (1-1) of Example 1 was carried out. ) by the same operation to obtain a film before stretching with a thickness of 198 μm including the polymer (C2).

(C2-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.65 times in the longitudinal direction at 146° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.85 times in the transverse direction at a temperature of 146°C (Tg+10°C) to obtain biaxial stretching film. Re of the obtained biaxially stretched film was 60 nm, Rth was 250 nm, and thickness d was 65 μm. Table 1 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 3]

(C3-1) Manufacture of film before stretching

Except that in (1-1) of Example 1, the polymer (C3) produced in Production Example 6 was used instead of the polymer (1) and the discharge amount of the molten resin was increased, the same process as in (1-1) of Example 1 was carried out. ) by the same operation to obtain a film before stretching with a thickness of 188 μm including the polymer (C3).

(C3-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.6 times in the longitudinal direction at 138° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.8 times in the transverse direction at a temperature of 138°C (Tg+10°C) to obtain biaxial stretching film. Re of the obtained biaxially stretched film was 60 nm, Rth was 250 nm, and thickness d was 65 μm. Table 2 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 4]

(C4-1) Manufacture of film before stretching

Except that the polymer (C4) produced in Production Example 7 was used instead of the polymer (1) in (1-1) of Example 1, the same operation as that of (1-1) of Example 1 was carried out to obtain Thickness of object (C4) is 136 μm before stretching.

(C4-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.35 times in the longitudinal direction at 112° C. (Tg + 10° C.) using a longitudinal stretcher using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.55 times in the transverse direction at a temperature of 112°C (Tg+10°C) to obtain biaxial stretching film. The Re of the obtained biaxially stretched film was 60 nm, the Rth was 300 nm, and the thickness was 65 μm. Table 2 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 5]

(C5-1) Manufacture of film before stretching

Except that the polymer (C3) produced in Production Example 6 was used instead of the polymer (1) in (1-1) of Example 1, the same operation as that of (1-1) of Example 1 was carried out to obtain Thickness of object (C3) was 134 μm before stretching.

(C5-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.2 times in the longitudinal direction at 138° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and tenter chain tension are adjusted, and at the same time stretched 1.4 times in the transverse direction at a temperature of 138°C (Tg+10°C) to obtain biaxial stretching film. The Re of the obtained biaxially stretched film was 60 nm, the Rth was 260 nm, and the thickness was 80 μm. Table 2 shows the results of an evaluation test performed on the obtained biaxially stretched film.

[Comparative Example 6]

(C6-1) Manufacture of film before stretching

Except that in (1-1) of Example 1, the polymer (C5) produced in Production Example 8 was used instead of the polymer (1) and the discharge amount of the molten resin was increased, the same process as in (1-1) of Example 1 was carried out. ) by the same operation to obtain a film before stretching with a thickness of 192 μm including the polymer (C5).

(C6-2) Manufacture of stretched film

Next, the film before stretching was stretched 1.62 times in the longitudinal direction at 180° C. (Tg + 10° C.) using a longitudinal stretching machine using a floating system between rolls. The film stretched in the longitudinal direction is further supplied to the transverse stretching machine using the tenter method, and the pulling tension and the tension of the tenter chain are adjusted, and at the same time, it is stretched 1.82 times in the transverse direction at a temperature of 180°C (Tg+10°C) to obtain biaxial stretching film. The Re of the obtained biaxially stretched film was 60 nm, the Rth was 250 nm, and the thickness was 65 μm. Table 2 shows the results of an evaluation test performed on the obtained biaxially stretched film.

The evaluation results of Examples and Comparative Examples are shown in the following tables. In the following tables, the meanings of abbreviations are as follows. MRu: MTF in which non-aromatic unsaturated bonds are selectively hydrogenated and aromatic unsaturated bonds remain. T: Hydrogenated TCD. D: Hydrogenated DCPD. M: MTF of hydrogenation (that is, MTF in which both non-aromatic unsaturated bonds and aromatic unsaturated bonds are hydrogenated). Polar COP: Cycloolefin polymers with polar groups. MD×TD: longitudinal extension ratio×transverse extension ratio.

"Table 1"

"Table 2"

[result]

As shown in Tables 1 and 2, in the stretched films of Examples satisfying the requirements of the present invention, although the stretching ratio was low, Rth/d was high, and the occurrence of delamination was suppressed. As a result, it was found that a viewing angle compensation film having excellent phase difference development and high retardation in the thickness direction can be provided by the film of the Example satisfying the requirements of the present invention.

none.

none.

Claims (6)

An optical film made of thermoplastic

It is an optical film made of vinyl resin, and it is a stretched film, wherein the aforementioned thermoplasticity is reduced.

The stress birefringence C _R of the ethylenic resin is not less than 2910×10 ^-12 Pa ^-1 and not more than 3900×10 ^-12 Pa ^-1 , the glass transition temperature Tg is not less than 125°C and not more than 180°C, and the thickness direction of the aforementioned optical film is The ratio (Rth/d) of the retardation Rth to the thickness d is not less than 3.5×10 ^-3 and not more than 8.0×10 ^-3 . The optical film according to claim 1, wherein the retardation Re in the in-plane direction is not less than 40 nm and not more than 80 nm. The optical film as claimed in item 1, wherein the aforementioned thermoplastic

Vinyl resins include polymers, the aforementioned polymers include resins having an aromatic ring structure

ethylenic monomer unit. The optical film as described in claim 3, wherein the aforementioned polymer comprises the aforementioned aromatic ring structure

The ethylenic monomer unit is 25% by weight or more. An optical stack comprising: the optical film according to any one of Claims 1 to 4, and a polarizing plate disposed on the optical film. A liquid crystal display device comprising the optical stack as described in Claim 5.