JP2018097121A - Composite film, production method, polarizing plate, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a composite film which can smoothly perform handling in production or use; a production method for easily producing the composite film; and a polarizing plate and a display device which can be easily produced at low cost.SOLUTION: There are provided: a composite film 10 which includes side regions (B) 121 and 122 of a pair of thermoplastic resins B, and a center region (A) 111 of a thermoplastic resin A provided between the side regions (B) 121 and 122 of the pair of thermoplastic resins B, where the thermoplastic resin A and the thermoplastic resin B are resins containing an alicyclic structure-containing polymer, the thermoplastic resin A, the thermoplastic resin B, the center region (A) 111 and the side regions (B) 121 and 122 satisfy a specific relationship; a production method of the same; and a polarizing plate and a display device containing a part of the same.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composite film, a manufacturing method thereof, a polarizing plate, and a display device.

  In an optical device such as a display device, a resin film is widely used, and as a material for supplying such a film, it is widely used to continuously produce a long film. It has been broken.

  In the production of such a long film, it is known to employ composite films having different materials in the central region in the width direction of the film and the side regions on both sides thereof (for example, Patent Document 1). . By adopting such a composite film, there is a possibility that effects such as smooth handling of the film can be obtained.

Japanese Patent Application Laid-Open No. 08-207119

  However, conventionally known composite films are still insufficient to reduce the problem of film handling smoothness. In particular, when the end in the width direction of a long film is gripped with a clip and handling such as transport, heating, and stretching is performed, the solution to the problem of the film sticking to the clip is still insufficient. Generation | occurrence | production of such sticking can raise the manufacturing cost of a film. Therefore, there is a demand for a composite film that can further reduce such sticking.

  Accordingly, an object of the present invention is to provide a composite film capable of smoothly handling in production or use; a production method capable of easily producing such a composite film; and easy production at low cost. Another object is to provide a polarizing plate and a display device.

The present inventor has studied to solve the above problems. As a result, the present inventor can solve this problem by adopting a combination of specific materials as the resin material constituting the central region of the composite film and the resin material constituting the side region. The present invention has been completed by finding out what can be done.
That is, the present invention is as follows.

[1] Central region (A) of the thermoplastic resin A provided between the side regions (B) of the pair of thermoplastic resins B and the side regions (B) of the pair of thermoplastic resins B And
The thermoplastic resin A and the thermoplastic resin B are resins containing an alicyclic structure-containing polymer,
The composite film in which the thermoplastic resin A, the thermoplastic resin B, the central region (A) and the side region (B) satisfy the following formulas (1) to (3):
Ea <Eb Formula (1)
Ts [B] −Ts [A] ≧ −10 ° C. Formula (2)
| RthB-RthA | ≧ 1 nm Formula (3)
Where Ea is the tensile elastic modulus of the thermoplastic resin A, Eb is the tensile elastic modulus of the thermoplastic resin B, Ts [A] is the thermal softening temperature of the thermoplastic resin A, and Ts [B] is the thermoplastic resin. The thermal softening temperature of B, RthA represents the thickness direction retardation of the central region (A), and RthB represents the thickness direction retardation of the side region (B).
[2] One or both of the thermoplastic resin A and the thermoplastic resin B are:
Two or more polymer blocks [D] per molecule based on a cyclic hydrocarbon group-containing compound hydride unit [I];
One or more polymer blocks [E] per molecule containing as a main component a chain hydrocarbon compound hydride unit [II] or a combination of the unit [I] and the unit [II]
The composite film as described in [1], comprising a hydrogenated block copolymer [G] containing as the alicyclic structure-containing polymer.
[3] The cyclic hydrocarbon group-containing compound unit [I] is a structural unit obtained by polymerization of an aromatic vinyl compound, and the chain hydrocarbon compound unit [II] is obtained by polymerization of a chain conjugated diene compound. The composite film according to [2], which is a structural unit obtained.
[4] The percentage Lb (%) of the ratio of the width direction width LB of the side region (B) to the width direction width L of the entire composite film satisfies the following formula (4): [1] to [ 3].
0.5% ≦ Lb ≦ 8% (4)
[5] A method for producing a composite film according to any one of [1] to [4],
The flow path (B1) of the thermoplastic resin B, the flow path (A) of the thermoplastic resin A, and the flow path (B2) of the thermoplastic resin B were arranged in this order in a direction corresponding to the width direction of the composite film. The manufacturing method including the extrusion process of extruding the said thermoplastic resin A and the said thermoplastic resin B from the extrusion apparatus provided in a state, and obtaining a film-form extrusion molding.
[6] The method for producing a composite film according to [5], further including a stretching step of stretching the extrudate in one or more directions after the extrusion step.
[7] The method for producing a composite film according to [6], wherein the stretching step includes gripping a width direction end portion of the extrudate with a clip and stretching in a width direction or an oblique direction.
[8] A polarizing plate comprising the central region (A) of the composite film according to any one of [1] to [4] and a polarizer.
[9] A display device comprising the central region (A) of the composite film according to any one of [1] to [4].

  The composite film of the present invention can be smoothly handled in production or use. In the production method of the present invention, such a composite film can be easily produced. The polarizing plate and display device of the present invention can be easily produced at low cost.

FIG. 1 is a cross-sectional view schematically showing a cross section of the composite film of the present invention cut along a plane perpendicular to the longitudinal direction. FIG. 2 is a graph showing transition regions of the thermoplastic resins A and B in the composite film 10 shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and exemplifications, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

  In the following description, the cyclic hydrocarbon group is a hydrocarbon group including a cyclic structure such as an aromatic ring, cycloalkane, or cycloalkene. The chain hydrocarbon compound is a hydrocarbon compound that does not contain such a cyclic hydrocarbon group.

  In the following description, the in-plane retardation Re of the film is a value represented by Re = (nx−ny) × d unless otherwise specified. The retardation Rth in the thickness direction of the film is a value represented by Rth = {(nx + ny) / 2−nz} × d unless otherwise specified. Here, nx represents a refractive index in a direction (in-plane direction) perpendicular to the thickness direction of the film and giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the film and perpendicular to the nx direction. The direction concerning nx and ny is prescribed | regulated separately in each of a center part area | region (A) and a side part area | region (B). nz represents the refractive index in the thickness direction of the film. d represents the thickness of the film. The measurement wavelength of retardation is 550 nm unless otherwise specified.

  In the following description, the “polarizing plate” includes not only a rigid member but also a flexible member such as a resin film, unless otherwise specified.

  In the following description, the “long” film means a film having a length of 5 times or more, preferably 10 times or more, and specifically a roll. A film having such a length that it can be wound up and stored or transported. The upper limit of the length of the long film is not particularly limited, and can be, for example, 100,000 times or less with respect to the width.

[1. Composite film)
The composite film of the present invention is a central portion of the thermoplastic resin A provided between the side region (B) of the pair of thermoplastic resins B and the side region (B) of the pair of thermoplastic resins B. Region (A). The composite film of the present invention is usually a long film having a certain width. The central region of the composite film is a central region in the width direction of the composite film, and the side region is a region outside the central portion in the width direction of the composite film. The composite film is usually a single layer film having only one layer in each of the central region (A) and the side region (B).

  FIG. 1 is a cross-sectional view schematically showing a cross section of the composite film of the present invention cut along a plane perpendicular to the longitudinal direction. In FIG. 1, the composite film 10 includes a central region (A) 111 and side regions (B) 121 and 122 provided on the side portions on both sides thereof. The central region (A) of the composite film may be composed of only the thermoplastic resin B. On the other hand, the side region (B) of the composite film may be composed of only the thermoplastic resin A.

In the composite film of the present invention, the central region (A) and the side region (B) and the thermoplastic resin A and the thermoplastic resin B constituting the same satisfy the following formulas (1) to (3).
Ea <Eb Formula (1)
Ts [B] −Ts [A] ≧ −10 ° C. Formula (2)
| RthB-RthA | ≧ 1 nm Formula (3)
Where Ea is the tensile modulus of the thermoplastic resin A, Eb is the tensile modulus of the thermoplastic resin B, Ts [A] is the thermal softening temperature of the thermoplastic resin A, and Ts [B] is the thermal softening of the thermoplastic resin B. Temperature, RthA represents the thickness direction retardation of the central region (A), and RthB represents the thickness direction retardation of the side region (B).

  Regarding the tensile elastic moduli Ea and Eb, the difference between Eb and Ea (Eb−Ea) is preferably 300 MPa or more, more preferably 400 MPa or more. Further, regarding the thermal softening temperatures Ts [A] and Ts [B], the difference (Ts [B] −Ts [A]) is −10 ° C. or higher, preferably −5 ° C. or higher. With Ea, Eb, Ts [A] and Ts [B] in this range, the composite film has a central region (A) with the desired optical and mechanical properties and is being handled. It can be set as the film with little generation | occurrence | production of sticking of the film to the clip. Such a composite film having Ea, Eb, Ts [A] and Ts [B] can be obtained by appropriately selecting the thermoplastic resins A and B constituting the film. Specific examples of the thermoplastic resins A and B will be described later.

  The upper limit of the difference between Eb and Ea (Eb−Ea) is not particularly limited, but may be, for example, preferably 2000 MPa or less, more preferably 1800 MPa or less. Each value of Ea and Eb is not particularly limited, but Ea is preferably 500 MPa or more, more preferably 700 MPa or more, preferably 3000 MPa or less, more preferably 2500 MPa or less. Eb is preferably 2000 MPa or more, more preferably 2100 MPa or more, preferably 4000 MPa or less, more preferably 3500 MPa or less.

  The tensile elastic moduli Ea and Eb can be measured by molding the resin to be measured into a 100 μm film and measuring it according to JIS K7127. Specifically, the film can be punched into a test piece type 1B dumbbell shape and used as a measurement sample, and measurement can be performed within a tensile speed of 20 mm / min and a tensile strain of 0.3% to 1%. As a measuring device, a tensile tester with a constant temperature and humidity chamber (for example, “5564 type” manufactured by Instron) can be used.

  The upper limit of the difference between Ts [A] and Ts [B] (Ts [B] −Ts [A]) is not particularly limited, but may be preferably 30 ° C. or less, more preferably 25 ° C. or less, for example. The values of Ts [A] and Ts [B] are not particularly limited, but Ts [A] is preferably 100 ° C. or higher, more preferably 105 ° C. or higher, preferably 155 ° C. or lower, more preferably 150. It is below ℃. Ts [B] is preferably 115 ° C or higher, more preferably 120 ° C or higher, preferably 160 ° C or lower, more preferably 155 ° C or lower.

  The thermal softening temperature Ts can be measured by TMA (thermomechanical analysis) measurement. Specifically, the resin to be measured is molded into a 5 mm × 20 mm × 50 μm film as a sample, and a tension of 50 mN is applied in the longitudinal direction of the sample using TMA / SS7100 (manufactured by SII Nanotechnology Co., Ltd.). In this state, the temperature (° C.) when the sample length is changed by 3% can be measured as the thermal softening temperature.

  Regarding the thickness direction retardations RthA and RthB, the value of | RthB−RthA | is 1 nm or more, preferably 1.2 nm or more. When the value of | RthB−RthA | is in such a range, the desired optical characteristics are given to the central region (A), and the boundary between the central region (A) and the side region (B) It can be easily recognized by optical measurement. The upper limit of the value of | RthB−RthA | is not particularly limited, but may be, for example, preferably 150 nm or less, more preferably 100 nm or less. A composite film having RthA and RthB satisfying such requirements can be obtained by appropriately selecting the thermoplastic resins A and B constituting the film and adjusting the production conditions as appropriate.

  Each value of RthA and RthB is not particularly limited, but | RthA | is preferably 0 nm or more, more preferably 0.1 nm or more, preferably 5 nm or less, more preferably 3 nm or less. | RthB | is preferably 0 nm or more, more preferably 0.1 nm or more, preferably 10 nm or less, more preferably 9 nm or less.

  RthA and RthB are obtained by measuring the thickness direction retardation in the central region (A) and the side region (B) using a commercially available retardation measuring device (for example, product name “RE” manufactured by Otsuka Electronics Co., Ltd.). It can be measured.

In the composite film of the present invention, it is preferable that the percentage Lb (%) of the ratio of the width direction width LB of the side region (B) to the entire width direction width L satisfies the following formula (4).
0.5% ≦ Lb ≦ 8% (4)

Referring to FIG. 1 again, the overall width L of the composite film 10 is a distance from one edge 101 in the width direction of the composite film 10 to the other edge 102.
Further, the width direction width LB of the side region (B) is the sum of the width of the side region (B) 121 and the width of 122. That is, LB is the distance from one edge 101 in the width direction of the composite film 10 to the boundary 131 between the side area (B) and the central area (A) closer to the edge 101, and the other. This is the total distance from the boundary 132 between the side region (B) and the central region (A) to the other edge 102 of the composite film 10.

  The percentage Lb of the width in the width direction is preferably 0.5% or more, more preferably 0.7% or more, preferably 8% or less, more preferably 7% or less. The width LB is preferably 15 mm or more, more preferably 20 mm or more. When Lb or LB is equal to or greater than the lower limit, handling can be performed smoothly by gripping the widthwise end of the long composite film with a clip. Further, when Lb is equal to or less than the upper limit, it is possible to reduce problems such as occurrence of film thickness unevenness during handling. The upper limit of the width direction width LB is not particularly limited, but is preferably 500 mm or less, more preferably 200 mm or less.

The width in the width direction of the side region (B) on one side of the composite film may be the same width as the width in the width direction of the side region (B) on the other side, or a different width. There may be. From the viewpoint of improving handling properties and reducing the occurrence of film thickness unevenness, it is preferable that the width in the width direction of the side regions (B) on both sides is the same or the difference is small. Specifically, the difference | LBL−LBR | between the width direction width LBL of one side region (B) and the width direction width LBR of the other side region (B) is preferably 50 mm or less, More preferably, it is 30 mm or less.
Furthermore, the characteristics (tensile modulus, thermal softening temperature, thickness direction phase difference, material, etc.) of the side region (B) on one side of the composite film and the side region (B) on the other side The features may be the same or different as long as both side regions (B) meet the requirements of the present invention. For example, the thickness direction retardation of the side region (B) on one side and the thickness direction retardation of the side region (B) on the other side are as long as both of these satisfy Expression (3). They may be the same or different.

  The boundary between the side region (B) and the central region (A) of the composite film may not always be clear. For example, when the composite film 10 shown in FIG. 1 is manufactured by extrusion molding of the thermoplastic resins A and B, a transition region composed of a mixture of the thermoplastic resins A and B can be formed at the boundaries 131 and 132. In such a transition region, a gradient of the concentration of the thermoplastic resins A and B can be formed. In that case, the position where the concentrations of the thermoplastic resins A and B show the central value of the gradient can be used as the boundary. Such a gradient is a physical property value of the thermoplastic resins A and B, and can be determined using an index indicating a different value between the thermoplastic resins A and B as an index.

  FIG. 2 is a graph showing transition regions of the thermoplastic resins A and B in the composite film 10 shown in FIG. In FIG. 2, the example of the measurement result at the time of measuring the thickness direction phase difference continuously along the width direction of the composite film 10 is shown. In FIG. 2, the horizontal axis indicates the distance in the width direction from one edge 101 of the composite film 10 to the measurement point, and the value x101 corresponding to the edge 101 is zero. On the other hand, the vertical axis represents the thickness direction retardation at the measurement point. In this example, the thickness direction retardation RthB of the side region (B) is a value indicated by y121, and the thickness direction retardation RthA of the central region (A) is a value indicated by y111. The average of RthA and RthB is a value indicated by yP. The region where there is a gradient in the concentration of the thermoplastic resins A and B is indicated by the curved portion of the graph. Here, since the central value of the gradient of the concentrations of the thermoplastic resins A and B is a position indicating the thickness direction phase difference indicated by yP, the position corresponding to the value x131 on the horizontal axis giving such yP is combined. It can be a boundary between the side region (B) and the central region (A) of the film.

  The thickness of the composite film is not particularly limited, and may be a desired thickness according to the application. Specifically, the thickness of the composite film is preferably 10 μm or more, more preferably 15 μm or more, preferably 100 μm or less, more preferably 60 μm or less. The thickness of the central region (A) and the thickness of the side region (B) may be the same or different, but both are preferably within the above-mentioned range.

  The thickness of the composite film can be measured by any known measuring method. For example, it can be measured using an interference type film thickness meter (for example, “F20-EXR” manufactured by Filmetrics).

  The composite film preferably has little film thickness unevenness in the central region (A). If there is little film thickness nonuniformity, a high quality product can be obtained by manufacturing products, such as a polarizing plate, using a center area | region (A). Specifically, the standard deviation when the thickness of the central region (A) is measured at 100 mm intervals over the entire width direction is preferably less than 1.5 μm, and more preferably less than 0.8 μm.

  The composite film of the present invention is usually a transparent layer and transmits visible light. In particular, the central region (A) preferably has a high light transmittance. The specific light transmittance can be appropriately selected according to the use of the composite film. For example, the light transmittance of the central region (A) at a wavelength of 420 nm to 780 nm is preferably 85% or more, more preferably 88% or more. By having such a high light transmittance, good display quality can be obtained when the central area (A) is mounted on a display device such as a liquid crystal display device.

[2. Thermoplastic resins A and B]
The thermoplastic resins A and B constituting the composite film of the present invention are both resins containing an alicyclic structure-containing polymer. Since both the thermoplastic resins A and B are resins containing an alicyclic structure-containing polymer, the material constituting these regions at the boundary between the central region (A) and the side region (B) is high. Affinity can be obtained.

[2.1. Hydrogenated block copolymer [G]]
In a preferred example, one or both of the thermoplastic resins A and B have two or more polymer blocks [D] having a cyclic hydrocarbon group-containing compound hydride unit [I], and a chain hydrocarbon compound hydrogen. Hydrogenated block copolymer [G] containing one or more polymer blocks [E] having a compound unit [II] or a combination of units [I] and units [II], and an alicyclic structure-containing polymer Include as. More preferably, only the thermoplastic resin A is a resin containing a hydrogenated block copolymer [G], and the thermoplastic resin B is another alicyclic structure-containing polymer-containing resin.

[2.1.1. Cyclic hydrocarbon group-containing compound hydride unit [I]]
Cyclic hydrocarbon group-containing compound hydride unit [I] polymerizes a cyclic hydrocarbon group-containing compound, and if the unit obtained by such polymerization has an unsaturated bond, the unsaturated bond is It is a structural unit having a structure obtained by hydrogenation. However, the cyclic hydrocarbon group-containing compound hydride unit [I] includes units obtained by any production method as long as it has the structure.

The cyclic hydrocarbon group-containing compound hydride unit [I] is preferably a structural unit obtained by polymerization of an aromatic vinyl compound. More specifically, it is a structural unit (aromatic vinyl compound hydride unit [I]) having a structure obtained by polymerizing an aromatic vinyl compound and hydrogenating an unsaturated bond thereof. However, the aromatic vinyl compound hydride unit [I] includes units obtained by any production method as long as it has the structure.
Similarly, in the present application, for example, a structural unit having a structure obtained by polymerizing styrene and hydrogenating the unsaturated bond may be referred to as a styrene hydride unit. The styrene hydride unit also includes a unit obtained by any production method as long as it has the structure.
Examples of the aromatic vinyl compound hydride unit [I] include structural units represented by the following structural formula (1).

In the structural formula (1), R ^c represents an alicyclic hydrocarbon group. Examples of R ^c include cyclohexyl groups such as cyclohexyl group; decahydronaphthyl groups and the like.

In the structural formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group or an imide group. Represents a chain hydrocarbon group substituted with a silyl group or a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ¹ , R ² and R ³ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

  Preferable specific examples of the aromatic vinyl compound hydride unit [I] include a structural unit represented by the following formula (1-1). The structural unit represented by Formula (1-1) is a styrene hydride unit.

  Any of the examples of the cyclic hydrocarbon group-containing compound hydride unit [I] having a stereoisomer can use any stereoisomer. One type of cyclic hydrocarbon group-containing compound hydride unit [I] may be used, or two or more types may be used in combination at any ratio.

[2.1.2. Chain hydrocarbon compound hydride unit [II]]
The chain hydrocarbon compound hydride unit [II] is obtained by polymerizing a chain hydrocarbon compound and further hydrogenating the unsaturated bond if the unit obtained by the polymerization has an unsaturated bond. Is a structural unit having the structure However, the chain hydrocarbon compound hydride unit [II] includes units obtained by any production method as long as it has the structure.

The chain hydrocarbon compound hydride unit [II] is preferably a structural unit obtained by polymerization of a diene compound. More specifically, a structural unit (diene compound hydrogen) having a structure obtained by polymerizing a diene compound and hydrogenating the unsaturated bond if the unit obtained by such polymerization has an unsaturated bond. Compound unit [II]). However, the diene compound hydride unit [II] includes units obtained by any production method as long as it has the structure.
Similarly, in the present application, for example, a structural unit having a structure obtained by polymerizing isoprene and hydrogenating the unsaturated bond may be referred to as an isoprene hydride unit. The isoprene hydride unit also includes a unit obtained by any production method as long as it has the structure.

  The diene compound hydride unit [II] is preferably a structural unit obtained by polymerization of a conjugated diene compound. More specifically, it preferably has a structure obtained by polymerizing a conjugated diene compound such as a chain conjugated diene compound and hydrogenating the unsaturated bond. Examples thereof include a structural unit represented by the following structural formula (2) and a structural unit represented by the structural formula (3).

In Structural Formula (2), R ^{4 to} R ⁹ are each independently a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group, an imide group, or a silyl group. Or a chain hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ^{4 to} R ⁹ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength, and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

In the structural formula (3), R ^{10 to} R ¹⁵ each independently represent a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group, an imide group, or a silyl group. Or a chain hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ^{10 to} R ¹⁵ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength, and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

  Preferable specific examples of the diene compound hydride unit [II] include structural units represented by the following formulas (2-1) to (2-3). The structural units represented by the formulas (2-1) to (2-3) are isoprene hydride units.

  In the examples of the chain hydrocarbon compound hydride unit [II], any one having a stereoisomer can be used. One type of chain hydrocarbon compound hydride unit [II] may be used, or two or more types may be used in combination at any ratio.

[2.1.3. Details of Hydrogenated Block Copolymer [G]
The hydrogenated block copolymer [G] preferably has a triblock molecular structure having one block [E] per molecule and two blocks [D] per molecule linked to both ends thereof. That is, the hydrogenated block copolymer [G] has one block [E] per molecule; and one end of the block [E] and has a cyclic hydrocarbon group-containing compound hydride unit [I]. One block [D1] per molecule; one block [D2] per molecule having a cyclic hydrocarbon group-containing compound hydride unit [I] connected to the other end of the block [E]; It is preferable that it is a triblock copolymer containing.

  In the hydrogenated block copolymer [G] as the triblock copolymer described above, from the viewpoint of easily obtaining a composite film having desirable characteristics, the total of the block [D1] and the block [D2] and the block [E] ] And the weight ratio (D1 + D2) / E are preferably within a specific range. Specifically, the weight ratio (D1 + D2) / E is preferably 45/55 or more, more preferably 50/50 or more, preferably 89/11 or less, more preferably 86/14 or less.

  Further, in the hydrogenated block copolymer [G] as the triblock copolymer described above, the weight ratio D1 between the block [D1] and the block [D2] from the viewpoint of easily obtaining a composite film having the above characteristics. / D2 is preferably within a specific range. Specifically, the weight ratio D1 / D2 is preferably 1 or more, more preferably 3 or more, particularly preferably 5 or more, preferably 15 or less, more preferably 14 or less, and particularly preferably 13 or less.

  The weight average molecular weight Mw of the hydrogenated block copolymer [G] is preferably 50000 or more, more preferably 55000 or more, particularly preferably 60000 or more, preferably 85000 or less, more preferably 80000 or less, and particularly preferably 75000. It is as follows. When the weight average molecular weight Mw is in the above range, a composite film having the above characteristics can be easily obtained. In particular, by reducing the weight average molecular weight, the retardation can be effectively reduced.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the hydrogenated block copolymer [G] is preferably 2.0 or less, more preferably 1.7 or less, and particularly preferably 1.5. Or less, preferably 1.0 or more. When the weight average molecular weight Mw is in the above range, the polymer viscosity can be lowered and the moldability can be improved. Moreover, the expression of retardation can be effectively reduced.

  The weight average molecular weight Mw and the number average molecular weight Mn of the hydrogenated block copolymer [G] can be measured as values in terms of polystyrene by gel permeation chromatography using tetrahydrofuran as a solvent.

  It is preferable that the block [D1] and the block [D2] each independently comprise only the cyclic hydrocarbon group-containing compound hydride unit [I], but other than the cyclic hydrocarbon group-containing compound hydride unit [I]. May contain any unit. Examples of arbitrary structural units include structural units based on vinyl compounds other than cyclic hydrocarbon group-containing compound hydride units [I]. The content of any structural unit in the block [D] is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less.

  The block [E] consists only of the chain hydrocarbon compound hydride unit [II], or only from the cyclic hydrocarbon group-containing compound hydride unit [I] and the chain hydrocarbon compound hydride unit [II]. Although it is preferable, arbitrary units other than the units [I] and [II] can be included. Examples of arbitrary structural units include structural units based on vinyl compounds other than the units [I] and [II]. The content of any structural unit in the block [E] is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less.

When the block [E] includes a cyclic hydrocarbon group-containing compound hydride unit [I] and a chain hydrocarbon compound hydride unit [II], the units [I] and [II] in the block [E] The weight ratio [I] / [II] is preferably 0.1 or more, more preferably 0.2 or more, particularly preferably 0.3 or more, preferably 1.5 or less, more preferably 1.4 or less. Particularly preferably, it is 1.3 or less.
The weight ratio [I] / [II] of the units [I] and [II] in the molecule of the hydrogenated block copolymer [G] is preferably 70/30 or more, more preferably 72/28 or more, Particularly preferably, it is 74/26 or more, preferably 89/11 or less, more preferably 87/13 or less, and particularly preferably 86/14 or less. When the ratio of the units [I] and [II] is in the above range, a composite film having the above characteristics can be easily obtained.

[2.1.4. Method for producing hydrogenated block copolymer [G]]
The manufacturing method of hydrogenated block copolymer [G] is not specifically limited, Arbitrary manufacturing methods can be employ | adopted. The hydrogenated block copolymer [G] is prepared, for example, by preparing monomers corresponding to the cyclic hydrocarbon group-containing compound hydride unit [I] and the chain hydrocarbon compound hydride unit [II]. The polymer [F] obtained by polymerization can be produced by hydrogenation.

  An aromatic vinyl compound can be used as the monomer that can give the hydride unit [I] of the cyclic hydrocarbon group-containing compound. Examples thereof include styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2 , 4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, monofluorostyrene, and 4-phenylstyrene Vinylcyclohexanes such as vinylcyclohexane and 3-methylisopropenylcyclohexane; and 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-vinylcyclohexene, 1-methyl-4-isopropenylcyclohexene, 2- Methyl And vinylcyclohexenes such as 4-vinylcyclohexene and 2-methyl-4-isopropenylcyclohexene. These monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Examples of monomers that can provide the chain hydrocarbon compound hydride unit [II] include butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. And chain conjugated dienes such as These monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  In general, anionic polymerization can be employed as a polymerization reaction mode. The polymerization may be performed by any of bulk polymerization and solution polymerization. Among these, solution polymerization is preferable in order to continuously perform the polymerization reaction and the hydrogenation reaction.

Examples of the solvent used in the polymerization reaction include aliphatic hydrocarbon solvents such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, And alicyclic hydrocarbon solvents such as decalin; and aromatic hydrocarbon solvents such as benzene and toluene. Among these, an aliphatic hydrocarbon solvent and an alicyclic hydrocarbon solvent are preferable because they can be used as they are as an inert solvent for the hydrogenation reaction.
A solvent may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
The solvent is usually used at a ratio of 200 to 10,000 parts by weight with respect to 100 parts by weight of the total monomers.

  In the polymerization, a polymerization initiator is usually used. Examples of polymerization initiators include monoorganolithiums such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, and phenyllithium; and dilithiomethane, 1,4-diobane, and 1,4-dilithiol A polyfunctional organolithium compound such as 2-ethylcyclohexane is exemplified. A polymerization initiator may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Production method of polymer [F] before hydrogenation in the case of producing a triblock copolymer containing block [D1], block [D2] and block [E] as hydrogenated block copolymer [G] Examples of the method include a production method including the following first to third steps. Here, the material called “monomer composition” includes not only a mixture of two or more kinds of substances but also a material composed of only a single substance.

First step: A step of polymerizing the monomer composition (d1) containing a cyclic hydrocarbon group-containing compound to form a block [d1] corresponding to the block [D1].
Second step: At one end of the block [d1], a monomer composition (e) containing a chain hydrocarbon compound or containing a cyclic hydrocarbon group-containing compound and a chain hydrocarbon compound is polymerized. Forming a block [e] corresponding to the block [E] to form a diblock polymer.
Third step: At the terminal on the block [e] side of the diblock polymer, the monomer composition (d2) containing the cyclic hydrocarbon group-containing compound is polymerized to obtain a triblock copolymer [F]. Obtaining. However, the monomer composition (d1) and the monomer composition (d2) may be the same or different.

  When polymerizing each polymer block, a polymerization accelerator and a randomizer can be used in order to prevent an excessively long chain of one component in each block. For example, when the polymerization is carried out by anionic polymerization, a Lewis base compound can be used as a randomizer. Specific examples of Lewis base compounds include ether compounds such as dimethyl ether, diethyl ether, diisopropyl ether, di-n-butyl ether, tetrahydrofuran, diphenyl ether, ethylene glycol diethyl ether, and ethylene glycol methyl phenyl ether; tetramethylethylenediamine, trimethylamine, triethylamine And tertiary amine compounds such as pyridine; alkali metal alkoxide compounds such as potassium tert-amyl oxide and potassium tert-butyl oxide; and phosphine compounds such as triphenylphosphine. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  The polymerization temperature is not limited as long as the polymerization proceeds, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, and is usually 200 ° C. or lower, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.

  After the polymerization, the polymer [F] can be recovered from the reaction mixture by any method if necessary. Examples of the recovery method include a steam stripping method, a direct desolvation method, and an alcohol coagulation method. Further, when a medium inert to the hydrogenation reaction is used as a solvent during polymerization, the polymer can be used as it is without recovering the polymer from the polymerization solution.

  There is no restriction | limiting in the method of hydrogenating a polymer [F] and making it a polymer [G], Arbitrary methods can be employ | adopted. Hydrogenation can be performed, for example, using a suitable hydrogenation catalyst. More specifically, hydrogenation is performed using a hydrogenation catalyst containing at least one metal selected from the group consisting of nickel, cobalt, iron, rhodium, palladium, platinum, ruthenium, and rhenium in an organic solvent. sell. The hydrogenation catalyst may be a heterogeneous catalyst or a homogeneous catalyst. A hydrogenation catalyst may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The heterogeneous catalyst may be used as it is as a metal or a metal compound, or may be used by being supported on an appropriate carrier. Examples of the carrier include activated carbon, silica, alumina, calcium carbide, titania, magnesia, zirconia, diatomaceous earth, and silicon carbide. The amount of the catalyst supported on the carrier is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 80% by weight or less, preferably 60% by weight or less.
Examples of homogeneous catalysts include catalysts combining nickel, cobalt, or iron compounds with organometallic compounds (eg, organoaluminum compounds, organolithium compounds); and rhodium, palladium, platinum, ruthenium, rhenium, etc. An organometallic complex catalyst is mentioned. Examples of nickel, cobalt, or iron compounds include acetylacetone salts, naphthenates, cyclopentadienyl compounds, and cyclopentadienyl dichloro compounds of these metals. Examples of organoaluminum compounds include alkylaluminums such as triethylaluminum and triisobutylaluminum; aluminum halides such as diethylaluminum chloride and ethylaluminum dichloride; and alkylaluminum hydrides such as diisobutylaluminum hydride.
Examples of the organometallic complex catalyst include metal complexes such as γ-dichloro-π-benzene complex, dichloro-tris (triphenylphosphine) complex, hydrido-chloro-triphenylphosphine) complex of each of the above metals. .
The amount of the hydrogenation catalyst used is usually 0.01 parts by weight or more, preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and usually 100 parts by weight with respect to 100 parts by weight of the polymer. Hereinafter, it is preferably 50 parts by weight or less, more preferably 30 parts by weight or less.

The reaction temperature during the hydrogenation reaction is usually 10 ° C. to 250 ° C., but is preferably 50 ° C. or more, more preferably, because the hydrogenation rate can be increased and the polymer chain scission reaction can be reduced. It is 80 degreeC or more, Preferably it is 200 degrees C or less, More preferably, it is 180 degrees C or less. Further, the pressure during the reaction is usually 0.1 MPa to 30 MPa, but in addition to the above reasons, from the viewpoint of operability, it is preferably 1 MPa or more, more preferably 2 MPa or more, preferably 20 MPa or less, more preferably 10 MPa or less.
The hydrogenation rate is usually 90% or more, preferably 95% or more, more preferably 97% or more. By increasing the hydrogenation rate, the low birefringence and thermal stability of the hydrogenated block copolymer [G] can be enhanced. The hydrogenation rate can be measured by ¹ H-NMR.

[2.2. Any component other than hydrogenated block copolymer [G]]
The thermoplastic resin A and / or B may be composed only of an alicyclic structure-containing polymer such as a hydrogenated block copolymer [G], but may optionally contain any other component.
Optional components include, for example, inorganic fine particles; stabilizers such as antioxidants, heat stabilizers, ultraviolet absorbers, near infrared absorbers; resin modifiers such as lubricants and plasticizers; colorants such as dyes and pigments And antistatic agents. As these arbitrary components, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio. However, from the viewpoint of remarkably exhibiting the effects of the present invention, it is preferable that the content of any component is small. For example, the ratio of the total of arbitrary components is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and still more preferably 3 parts by weight or less with respect to 100 parts by weight of the alicyclic structure-containing polymer.

[2.3. Other alicyclic structure-containing polymer]
The thermoplastic resin B is a material different from the thermoplastic resin A at least in terms of different tear strengths when formed into a film. As the thermoplastic resin B, a resin that can give a composite film satisfying the requirements of the present invention among resins containing an alicyclic structure-containing polymer can be adopted.

Specific examples of the thermoplastic resin when the thermoplastic resin A and / or B is a resin other than the resin containing the hydrogenated block copolymer [G] described above include an alicyclic structure described below. A polymer containing resin is mentioned.
The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and a polymer having an alicyclic structure in the main chain and a polymer having an alicyclic structure in the side chain. Any of these can be used. The alicyclic structure-containing polymer includes a crystalline resin and an amorphous resin, but an amorphous resin is preferable from the viewpoint of obtaining the desired effect of the present invention and the manufacturing cost.

  Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability.

  Although there is no restriction | limiting in particular in carbon number which comprises the repeating unit of one alicyclic structure, Usually, 4-30, Preferably it is 5-20, More preferably, it is 6-15.

  The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is appropriately selected according to the purpose of use, but is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight. That's it. By increasing the number of repeating units having an alicyclic structure in this way, the heat resistance of the base film can be increased.

  Specifically, the alicyclic structure-containing polymer includes (1) norbornene polymer, (2) monocyclic olefin polymer, (3) cyclic conjugated diene polymer, and (4) vinyl alicyclic hydrocarbon. Examples thereof include polymers and hydrides thereof. Among these, from the viewpoints of transparency and moldability, norbornene polymers and hydrides thereof are more preferable.

Examples of the norbornene polymer include a ring-opening polymer of a norbornene monomer, a ring-opening copolymer of a norbornene monomer and another monomer capable of ring-opening copolymerization, and a hydride thereof; an addition polymer of a norbornene monomer, norbornene Examples thereof include addition copolymers with other monomers copolymerizable with the monomers. Among these, a ring-opening polymer hydride of a norbornene monomer is particularly preferable from the viewpoint of transparency.
Said alicyclic structure containing polymer is chosen from the polymer currently disclosed by Unexamined-Japanese-Patent No. 2002-321302, for example.

  The alicyclic structure-containing polymer has a glass transition temperature of preferably 80 ° C or higher, more preferably 100 ° C to 250 ° C. An alicyclic structure-containing polymer having a glass transition temperature in such a range is less susceptible to deformation and stress during use at high temperatures and is excellent in durability.

  The molecular weight of the alicyclic structure-containing polymer is converted to polyisoprene measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using cyclohexane (toluene when the resin is not dissolved) as a solvent. (When the solvent is toluene, the weight average molecular weight (Mw) in terms of polystyrene) is usually 10,000 to 100,000, preferably 25,000 to 80,000, more preferably 25,000 to 50,000. is there. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the base film are highly balanced.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer is usually 1 to 10, preferably 1 to 4, more preferably 1.2 to 3.5. .

  The resin containing the alicyclic structure-containing polymer may be composed only of the alicyclic structure-containing polymer, but may contain any compounding agent as long as the effects of the present invention are not significantly impaired. The ratio of the alicyclic structure-containing polymer in the resin is preferably 70% by weight or more, more preferably 80% by weight or more.

  Since various products are commercially available as the resin containing the alicyclic structure-containing polymer, those having desired characteristics can be appropriately selected and used as the resin A and / or B. Examples of such commercially available products include a product group having a trade name “ZEONOR” (manufactured by Nippon Zeon Co., Ltd.).

[3. (Production method of composite film)
The manufacturing method of the composite film of this invention is not specifically limited, Arbitrary manufacturing methods can be employ | adopted. For example, the composite film of the present invention can be produced by preparing Resin A to Resin B and molding them into a desired shape. Preferable examples of the molding method for molding the resin A to the resin B include extrusion molding by coextrusion. By performing extrusion molding, a composite film having a desired region size can be efficiently produced.

  The temperature of the resin during coextrusion molding (hereinafter sometimes referred to as “extrusion temperature” as appropriate) is not particularly limited, and is a temperature at which each resin can be melted, and a temperature suitable for molding is appropriately selected. Can be set. Specifically, the higher Ts [H] of Ts [A] and Ts [B] can be set as a reference. More specifically, it is preferably (Ts [H] +90) ° C. or higher, more preferably (Ts [H] +100) ° C. or higher, while preferably (Ts [H] +170) ° C. or lower, more preferably It is (Ts [H] +160) ° C. or lower.

  As an extrusion apparatus for performing extrusion molding, the flow path (A1) of the thermoplastic resin A, the flow path (B) of the thermoplastic resin B, and the flow path (A2) of the thermoplastic resin A are in this order in the composite film. The extrusion apparatus provided in the state arranged in the direction corresponding to the width direction may be used. By extruding the thermoplastic resin A and the thermoplastic resin B from such an extrusion device, the central region (A) of the thermoplastic resin B and the side portions of the thermoplastic resin A provided on both side portions thereof. A long film-like extrudate comprising the region (B) can be obtained. Specific examples of the extrusion apparatus include an apparatus described in JP-A-2014-177004.

  The obtained extruded product can be used as it is as the composite film of the present invention. Alternatively, this resin film is further subjected to an arbitrary treatment, and the resulting film can be used as the composite film of the present invention. Examples of the optional treatment include operations such as trimming, stretching and the like of part or all of the side region of the extruded product.

  In the production or use of the composite film of the present invention, as an optional treatment, when the processing is performed such that the end in the width direction of the extrudate is held by a clip and handling such as conveyance, heating, and stretching is performed. The benefits of this can be enjoyed particularly well. A clip for performing such handling may be deformed on the gripping surface due to an impact or the like due to use of the apparatus, and the deformation may cause a protrusion on the gripping surface. When the extruded product comes into contact with the protrusions, a hole may be formed in the extruded product, and breakage may occur starting from the hole. However, in the production or use of the composite film of the present invention, the occurrence of such breakage can be suppressed due to the structure of the specific central region (A) and side region (B). Therefore, the composite film of the present invention is useful because it can reduce the cost in production and use.

  The composite film, which is a stretched film, is specifically stretched in at least one direction after subjecting the extruded product obtained by the above-described method or the like to an operation such as trimming as necessary. It can be manufactured by a manufacturing method including a process. By appropriately adjusting the proportion of the structural unit contained in the hydrogenated block copolymer [G], it is possible to reduce the retardation developed in the film by stretching. Therefore, a composite film satisfying the preferable relationship between ReA and ReB can be easily manufactured, and the manufacturing efficiency can be improved.

  The stretching conditions of the extruded product in the case of producing a stretched film as a composite film can be appropriately adjusted so that the composite film described above can be obtained. The stretching performed in the stretching process can be uniaxial stretching, biaxial stretching, or other stretching. The stretching direction can be set in any direction. For example, the stretching direction may be any of the longitudinal direction, the width direction, and other oblique directions of the extruded product. The angle formed by the two stretching directions when biaxial stretching is performed can usually be an angle orthogonal to each other, but is not limited thereto, and may be an arbitrary angle. Biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching.

  In a preferred example, the stretching of the extrudate includes gripping the widthwise end of the extrudate with a clip and stretching in the width direction or oblique direction. When performing such stretching, the benefits of the present invention can be enjoyed particularly well for the reasons described above.

  The stretching temperature when stretching the extruded product can be set based on Ts [A]. Specifically, it is preferably (Ts [A] +15) ° C. or higher, more preferably (Ts [A] +20) ° C. or higher, preferably (Ts [A] +90) ° C. or lower, more preferably ( Ts [A] +70) ° C. or lower. When the stretching temperature falls within the above temperature range, a stretched film as a composite film having the above characteristics can be easily obtained.

  The stretching ratio when stretching the extruded product is preferably 1.01 times or more, more preferably 1.05 times or more, particularly preferably 1.10 times or more, preferably 2.00 times or less, more Preferably it is 1.70 times or less, Most preferably, it is 1.50 times or less. When the draw ratio falls within the above temperature range, a stretched film as a composite film having the above properties can be easily obtained. In the case of biaxial stretching, the magnification in each of the two stretching directions can be within this range.

[4. Application of composite film: Polarizing plate and display device]
The composite film of the present invention can be used as a material for an optical device such as a display device. Specifically, the central region (A) is cut out from the composite film, and this can be combined with other members to constitute an optical component such as a polarizing plate.

  The aspect which cuts out center part area | region (A) from a elongate composite film is not specifically limited, What kind of aspect may be sufficient. For example, a rectangular film suitable for the shape of the display surface of the display device can be directly cut out from the central area (A) of the long film. Alternatively, a side film (B) of a long film is trimmed to form a long film consisting only of the central area (A) or including the central area (A) and the narrow side area (B). This may be stored as a film roll, and a rectangular film suitable for the shape of the display surface of the display device may be cut out from the film roll. In the film roll, the masking film may be superposed on the film including the central region (A) as necessary to suppress blocking of the film.

  Prior to use of the composite film, an arbitrary layer may be provided on the surface of the composite film. Examples of optional layers include a hard coat layer that increases the surface hardness of the film, a matte layer that improves the slipperiness of the film, and an antireflection layer.

  The composite film of the present invention can be suitably used as a material for forming a protective film for protecting other layers in a display device such as a liquid crystal display device. Especially, the center area | region (A) of the composite film of this invention is suitable as a polarizer protective film, and is especially suitable as a polarizer protective film located in the outermost surface of a display apparatus.

  The polarizing plate of the present invention comprises the central region (A) of the composite film of the present invention and a polarizer. In the polarizing plate of the present invention, the central region (A) of the composite film can function as a polarizer protective film. The central region (A) of the composite film may be a film having an arbitrary shape cut out from the composite film. The cut out film usually consists of only the central region (A), but may include the side region (B) as long as it can be used as a polarizing plate. The polarizing plate of the present invention may further include an adhesive layer for bonding these films between the film cut from the composite film and the polarizer.

  The polarizer is not particularly limited, and any polarizer can be used. Examples of the polarizer include those obtained by adsorbing a material such as iodine or a dichroic dye on a polyvinyl alcohol film and then stretching the material. Examples of the adhesive constituting the adhesive layer include those using various polymers as a base polymer. Examples of such base polymers include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and synthetic rubbers.

  The number of polarizers and protective films provided in the polarizing plate is arbitrary, but the polarizing plate of the present invention can usually comprise a single layer of polarizer and two layers of protective films provided on both sides thereof. Of these two protective films, both may be films cut from the composite film of the present invention, or only one of them may be a film cut from the composite film of the present invention.

The display device of the present invention includes the central region (A) of the composite film of the present invention. The display device of the present invention can preferably include the polarizing plate of the present invention as the central region (A) of the composite film.
The display device of the present invention is preferably a liquid crystal display device. Examples of the liquid crystal display device include an in-plane switching (IPS) mode, a vertical alignment (VA) mode, a multi-domain vertical alignment (MVA) mode, a continuous spin wheel alignment (CPA) mode, a hybrid alignment nematic (HAN) mode, Examples of the liquid crystal display device include a liquid crystal cell of a driving system such as a twisted nematic (TN) mode, a super twisted nematic (STN) mode, and an optically compensated bend (OCB) mode.
When the display device of the present invention is a liquid crystal display device, the polarizing plate can be provided as a layer for transmitting only a specific polarized light out of light incident on the liquid crystal cell and light emitted from the liquid crystal cell. The polarizing plate can also be provided as a part of a component for preventing reflection of external light.

  The display device of the present invention may also be an organic electroluminescence display device. In this case, for example, a polarizing plate including the central region (A) of the composite film of the present invention is provided as a part of a component for preventing reflection of external light.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.
In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.

〔Evaluation method〕
[Weight average molecular weight and number average molecular weight]
The weight average molecular weight and number average molecular weight of the polymer were measured as polystyrene equivalent values using a gel permeation chromatography (GPC) system (“HLC-8320” manufactured by Tosoh Corporation). In the measurement, an H type column (manufactured by Tosoh Corporation) was used as the column, and tetrahydrofuran was used as the solvent. Moreover, the temperature at the time of measurement was 40 degreeC.
The polymerization addition rate during the synthesis of the polymer was appropriately measured by GPC and gas chromatography.

[Hydrogenation rate of hydrogenated block copolymer]
The hydrogenation rate of the polymer was measured by ¹ H-NMR measurement at 145 ° C. using orthodichlorobenzene-d ₄ as a solvent.

[Thermal softening temperature Ts]
A resin to be measured was molded into a film of 5 mm × 20 mm × 50 μm to prepare a sample. As a measuring device, TMA / SS7100 (manufactured by SII Nanotechnology Inc.) was used. In TMA (thermomechanical analysis) measurement, the temperature was changed with a tension of 50 mN applied in the longitudinal direction of the sample. The temperature (° C.) when the sample length was changed by 3% was defined as the thermal softening temperature.

[In-plane retardation, thickness direction retardation, and width of side region (B) in width direction]
An in-plane retardation Re and a thickness direction retardation Rth of the continuously conveyed film were measured using a phase difference measuring device (product name “RE” manufactured by Otsuka Electronics Co., Ltd.). The measurement wavelength was 550 nm. The measurement was performed at a large number of measurement points by moving the measurement points at intervals of 5 mm over the entire width in the composite film width direction. In a region where the gradient of Rth exists in the transition region between the central region (A) and the side region (B), a position corresponding to the measurement point indicating the central value of the gradient is obtained, and such a position is combined. Based on the boundary between the side area (B) and the central area (A) of the film, based on this, the width direction width LB of the side area (B) and the width direction width L of the entire composite film The percentage Lb (%) of the ratio was determined. The average of the measurement results at the measurement points in the central region (A) was ReA and RthA, and the average of the measurement results at the measurement points in the side region (B) was ReB and RthB.

[Tensile modulus]
The tensile elastic modulus was measured according to JIS K7127. The resin to be measured was formed into a 100 μm unstretched film, punched into a test piece type 1B dumbbell shape, and used as a measurement sample. As a measuring device, a tensile tester with a constant temperature and humidity chamber (“5564 type” manufactured by Instron) was used. Moreover, the elastic modulus was computed in the range of 20 mm / min and the tensile strain of 0.3%-1% for the tensile speed.

[Evaluation of sticking to clip]
In Examples 4 to 6 and Comparative Examples 1 and 2, the degree of sticking of the film to the clip in the step of drawing the film before stretching to obtain a composite film was evaluated.
On the other hand, in Examples 1 to 3, the degree of sticking of the film to the clip in the step of further stretching the obtained composite film was evaluated. The tenter type transverse stretching machine was used for stretching, and the composite film was continuously stretched by holding both ends of the composite film with clips. At the time of stretching, the stretching ratio was 1.2 times. Stretching was performed in an oven and the stretching temperature was 170 ° C.
In the oven, the case where the film stuck to the clip was evaluated as “bad”, and the case where the film did not occur was evaluated as “good”.

[Production Example 1]
(P1-1. Production of block copolymer [F1])
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 55 parts of styrene, and 0.38 part of di-n-butyl ether, and stirred at 60 ° C. The first stage polymerization reaction was initiated by adding 0.56 parts of a butyllithium solution (15 wt% hexane solution). Furthermore, it was made to react at 60 degreeC for 60 minutes, stirring. The polymerization conversion rate at this time was 99.5%. The reaction temperature was maintained at 60 ° C. until the reaction was stopped.
Next, 40 parts of a mixed monomer composed of 20 parts of styrene and 20 parts of isoprene was added to the reaction solution, and then the second stage polymerization reaction was started. At 1 hour after the start of the second stage polymerization reaction, the polymerization conversion was 99.5%.

  Thereafter, 5 parts of styrene was further added to the reaction mixture, and then the third stage polymerization reaction was started. As a result of sampling and analyzing a sample from the reaction mixture at 1 hour after the start of the third stage polymerization reaction, the polymerization conversion was almost 100%. Immediately thereafter, 0.2 part of isopropyl alcohol was added to the reaction mixture to stop the reaction. This obtained the mixture containing the block copolymer [F1] which has a triblock molecular structure of D1-E-D2.

Since the polymerization reaction was sufficiently advanced in the above reaction, the polymerization conversion rate was about 100%. Therefore, the weight ratio of St / Ip in block E is considered to be 20/20.
From these values, it is found that the obtained block copolymer [F1] is a polymer having a triblock molecular structure of St- (St / Ip) -St = 55- (20/20) -5. It was.

(P1-2. Hydrogenated block copolymer [G1])
The mixture containing the block copolymer [F2] obtained in (P1-1) was transferred to a pressure resistant reactor equipped with a stirrer, and a diatomaceous earth supported nickel catalyst (product name “E22U”, nickel) as a hydrogenation catalyst. (Supported amount 60%, manufactured by JGC Catalysts & Chemicals Co., Ltd.) 8.0 parts and dehydrated cyclohexane 100 parts were added and mixed. The inside of the reactor was replaced with hydrogen gas, and hydrogen was supplied while stirring the solution. A hydrogenation reaction was performed at a temperature of 190 ° C and a pressure of 4.5 MPa for 6 hours. The reaction solution obtained by the hydrogenation reaction contained the hydrogenated block copolymer [G1]. The weight average molecular weight (Mw) of the hydrogenated block copolymer [G1] was 76,000, and the molecular weight distribution (Mw / Mn) was 1.05.

After completion of the hydrogenation reaction, the reaction solution was filtered to remove the hydrogenation catalyst, and then the phenol-based antioxidant pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl). ) Propionate] (product name “AO60”, manufactured by ADEKA) 2.0 parts of xylene solution in which 0.1 part was dissolved was added and dissolved to obtain a solution.
Next, the solution is treated at a temperature of 260 ° C. and a pressure of 0.001 MPa or less using a cylindrical concentration dryer (product name “Contro”, manufactured by Hitachi, Ltd.). From the solution, the solvents cyclohexane, xylene and Other volatile components were removed to obtain a molten resin. This was extruded from a die into a strand, cooled, and formed into pellets by a pelletizer. As a result, 95 parts of a pellet of the resin [G1] containing the hydrogenated block copolymer [G1] was produced.
The weight average molecular weight (Mw) of the hydrogenated block copolymer [G1] in the obtained resin [G1] was 77,000, the molecular weight distribution (Mw / Mn) was 1.06, and the hydrogenation rate was almost 100%. It was. The thermal softening temperature Ts was 128 ° C. The tensile elastic modulus measured for the resin [G1] was 1600 MPa.

[Production Example 2]
(P2-1) Production of block copolymer [F2] In a reactor equipped with a stirrer and sufficiently purged with nitrogen inside, 270 parts of dehydrated cyclohexane, 75 parts of dehydrated styrene and 7.0 parts of di-n-butyl ether Put. While stirring the whole volume at 60 ° C., 5.6 parts of n-butyl lithium (15% cyclohexane solution) was added to initiate polymerization. Subsequently, the whole volume was stirred at 60 ° C. for 60 minutes. The reaction temperature was maintained at 60 ° C. until the reaction was stopped.
The polymerization conversion rate at this point (polymerization first stage) was 99.4%.

Next, 15 parts of dehydrated isoprene was continuously added to the reaction solution over 40 minutes, and stirring was continued for 30 minutes as it was after the addition was completed. The polymerization conversion rate at this point (polymerization second stage) was 99.8%.
Thereafter, 10 parts of dehydrated styrene was continuously added to the reaction solution over 30 minutes, and stirred for 30 minutes as it was after completion of the addition. The polymerization conversion rate at this point (polymerization third stage) was almost 100%.

  Here, 1.0 part of isopropyl alcohol was added to stop the reaction, thereby obtaining a polymer solution containing a block copolymer [F2] of [D1]-[E]-[D2] type. In the obtained block copolymer [F2], Mw [F4] = 82,400, Mw / Mn was 1.32 and wA: wB = 85: 15.

(P2-2) Production of hydrogenated block copolymer [G2] The polymer solution obtained in (P2-1) is transferred to a pressure-resistant reactor equipped with a stirrer, and diatomaceous earth supported nickel as a hydrogenation catalyst. 4.0 parts of a catalyst (product name “E22U”, nickel loading 60%, manufactured by JGC Catalysts & Chemicals Co., Ltd.) and 30 parts of dehydrated cyclohexane were added and mixed. The inside of the reactor was replaced with hydrogen gas, and hydrogen was supplied while stirring the solution. A hydrogenation reaction was performed at a temperature of 190 ° C and a pressure of 4.5 MPa for 6 hours.
The reaction solution obtained by the hydrogenation reaction contained the hydrogenated block copolymer [G2]. Mw [G4] of the hydrogenated block copolymer [G2] was 71,800, the molecular weight distribution Mw / Mn was 1.30, and the hydrogenation rate was almost 100%.

After completion of the hydrogenation reaction, the reaction solution was filtered to remove the hydrogenation catalyst, and then the phenol-based antioxidant pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl). ) Propionate] (product name “AO60”, manufactured by ADEKA) 2.0 parts of xylene solution in which 0.3 part was dissolved was added and dissolved to obtain a solution.
Next, the above solution is treated at a temperature of 260 ° C. and a pressure of 0.001 MPa or less using a cylindrical concentrating dryer (product name “Contro”, manufactured by Hitachi, Ltd.), and cyclohexane, xylene and other volatile components are removed from the solution. And a molten resin was obtained. This was extruded from a die into a strand, cooled, and formed into pellets by a pelletizer. As a result, 95 parts of a pellet of the resin [G2] containing the hydrogenated block copolymer [G2] was produced.
The obtained hydrogenated block copolymer [G2] in the resin [G2] had Mw [G2] = 68,500, Mw / Mn = 1.30, and Ts = 139 ° C. The tensile elastic modulus measured for the resin [G2] was 1860 MPa.

[Production Example 3]
(P3-1. Production of block copolymer [F3])
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 256 parts of dehydrated cyclohexane, 25.0 parts of dehydrated styrene, and 0.65 part of di-n-butyl ether and stirred at 60 ° C. While adding 0.82 part of n-butyllithium (15% cyclohexane solution), the polymerization reaction was started. Furthermore, it was made to react at 60 degreeC for 60 minutes, stirring. The polymerization conversion rate at this time was 99.5%. The reaction temperature was maintained at 60 ° C. until the reaction was stopped.
Next, 50 parts of a mixed monomer composed of 25 parts of styrene monomer and 25 parts of isoprene monomer was continuously added to the reaction solution over 150 minutes, and stirring was continued for 20 minutes after completion of the addition. The polymerization conversion rate at this time was 99.5%. Thereafter, 25.0 parts of dehydrated styrene was further added and stirred for 60 minutes. The polymerization conversion rate at this point was almost 100%. Next, 0.5 part of isopropyl alcohol was added to the reaction solution to stop the reaction, and a polymerization reaction solution containing a block copolymer [F3] was obtained. The obtained block copolymer [F3] had a weight average molecular weight (Mw) of 58,000 and a molecular weight distribution (Mw / Mn) of 1.03.

(P3-2. Production of hydrogenated block copolymer [G3])
The polymerization reaction solution obtained in (P3-1) was transferred to a pressure-resistant reactor equipped with a stirrer, and a silica-alumina supported nickel catalyst (E22U, nickel supported amount 60%; manufactured by JGC Chemical Industries, Ltd.) as a hydrogenation catalyst. ) 4.0 parts and 350 parts dehydrated cyclohexane were added and mixed. The inside of the reactor was replaced with hydrogen gas, and hydrogen was supplied while stirring the solution. A hydrogenation reaction was performed at a temperature of 170 ° C. and a pressure of 4.5 MPa for 6 hours.
After completion of the hydrogenation reaction, the reaction solution was filtered to remove the hydrogenation catalyst. To the filtrate, pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (product name “AO60”, manufactured by ADEKA), which is a phenolic antioxidant, was added. 1.0 part of a xylene solution in which 1 part was dissolved was added and dissolved to obtain a solution.
Next, the above solution is treated at a temperature of 260 ° C. and a pressure of 0.001 MPa or less using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd., product name “Contro”). The volatile component was removed to obtain a molten resin. This was filtered at a temperature of 260 ° C. with a polymer filter (manufactured by Fuji Filter Co., Ltd.) equipped with a stainless sintered filter having a pore diameter of 20 μm connected to a concentration dryer, and then the molten polymer was extruded from the die into a strand shape, cooled, The pellet was formed by a pelletizer. As a result, a pellet of the resin [G3] containing the hydrogenated block copolymer [G3] was obtained.
The hydrogenated block copolymer [G3] in the obtained resin [G3] is a block in which St, a repeating unit derived from styrene and a repeating unit derived from isoprene coexist (hereinafter referred to as “St / Ip” as appropriate). The weight ratio of each block was St: St / Ip: St = 25: 25/25: 25. The block copolymer had Mw of 59,000, Mw / Mn of 1.05, a hydrogenation rate of almost 100%, and a thermal softening temperature Ts of 110 ° C. The tensile elastic modulus measured for the resin [G3] was 800 MPa.

[Example 1]
(1-1. Extruded product)
A double flight type single screw extruder (screw diameter D = 50 mm, screw length L to screw diameter D ratio L / D = 28) equipped with a leaf disk-shaped polymer filter with a mesh opening of 3 μm was prepared. . Into this single screw extruder, the resin [G1] obtained in Production Example 1 was introduced as the thermoplastic resin A, melted, supplied to both ends in the width direction of the feed block, and then supplied to the single-layer die. The resin [G1] was introduced into the single screw extruder through a hopper loaded in the single screw extruder. Moreover, the surface roughness (arithmetic mean roughness Ra) of the die slip of the single-layer die was 0.1 μm.

  On the other hand, a single-screw extruder (screw diameter D = 50 mm, screw length L / screw diameter D ratio L / D = 30) having a leaf disk-shaped polymer filter with a mesh opening of 3 μm was prepared. . In this single screw extruder, as the thermoplastic resin B, a resin [Z1] containing a polymer containing an alicyclic structure (manufactured by Nippon Zeon Co., Ltd., trade name “Zeonor”, thermal softening temperature 128 ° C., tensile modulus 2300 MPa ) Was introduced, dissolved, and fed to the center in the width direction of the feed block, and fed to the single-layer die.

The thermoplastic resins A and B are discharged from a single-layer die in a molten state at 250 ° C. (coextrusion molding process), thereby having a film-like shape and a central region (A) of the thermoplastic resin A The molten resin comprising the side regions (B) of the thermoplastic resin B provided on the side portions on both sides of the central region (A) was continuously molded.
The film-like molten resin was cast on a cooling roll and cooled. At the time of casting, the air gap amount was set to 40 mm. Moreover, edge pinning was adopted as a casting method. Thereby, a long film-like extruded product was obtained. The obtained extruded product includes a central region (A) of the thermoplastic resin A and side regions (B) of the thermoplastic resin B provided on both sides of the central region (A). The film was 2300 mm wide in the width direction.

(1-2. Composite film)
Both ends of the extruded product obtained in (1-1) were trimmed to obtain a long composite film having a width in the width direction of 2200 mm, and this was evaluated. The thickness of this composite film was 50 μm. The width direction width of (side area (B)) / (center area (A)) / (side area (B)) was 10 mm / 2180 mm / 10 mm. The in-plane retardation ReA of the central region (A) was 1.1 nm, and the thickness direction retardation RthA was 0.2 nm. The in-plane retardation ReB of the side region (B) was 1.2 nm, and the thickness direction retardation RthB was 7.3 nm. Table 1 shows the evaluation results of sticking of the composite film to the clip.

[Example 2]
(2-1. Extruded product)
Except for the following changes, the same operation as in (1-1) of Example 1 was performed to obtain an extruded product.
In place of the resin [G1] obtained in Production Example 1, the resin [G2] obtained in Production Example 2 was used.
In place of the resin [Z1], a resin [Z2] containing a polymer containing an alicyclic structure (manufactured by Nippon Zeon Co., Ltd., trade name “ZEONOR”, heat softening temperature 136 ° C., tensile elastic modulus 2350 MPa) was used. .
-The size of the flow path of the resin in the feed block was changed, thereby changing the ratio of the width in the width direction of the side region (B) to the width in the width direction of the entire extruded product. As a result, the width in the width direction of (side region (B)) / (center region (A)) / (side region (B)) in the composite film was as shown in Table 1.

(2-2. Composite film)
The same operation as (1-2) of Example 1 was performed except that the extruded product obtained in (2-1) was used instead of the extruded product obtained in (1-1) of Example 1. A composite film was obtained and evaluated.

Example 3
(3-1. Extruded product)
Except for the following changes, the same operation as in (1-1) of Example 1 was performed to obtain an extruded product.
In place of the resin [G1] obtained in Production Example 1, the resin [G3] obtained in Production Example 3 was used.
-The size of the flow path of the resin in the feed block was changed, thereby changing the ratio of the width in the width direction of the side region (B) to the width in the width direction of the entire extruded product. As a result, the width in the width direction of (side region (B)) / (center region (A)) / (side region (B)) in the composite film was as shown in Table 1.

(3-2. Composite film)
The same operation as (1-2) of Example 1 was performed except that the extruded product obtained in (3-1) was used instead of the extruded product obtained in (1-1) of Example 1. A composite film was obtained and evaluated.

Example 4
(4-1. Composite film)
Both ends of the extruded product obtained in (1-1) of Example 1 were trimmed to obtain a long unstretched film having a width in the width direction of 2200 mm. Using a tenter-type transverse stretching machine, both ends of the unstretched film were held with clips, and the unstretched film was continuously stretched to obtain a stretched composite film. At the time of stretching, the stretching ratio was 1.2 times. Moreover, extending | stretching was performed in oven and the extending | stretching temperature was 170 degreeC. The resulting composite film had a thickness of 42 μm. In the composite film, the width in the width direction of (side region (B)) / (center region (A)) / (side region (B)) was 10 mm / 2620 mm / 10 mm. The in-plane retardation of the central region (A) and the side region (B), the thickness direction retardation, and the evaluation results of sticking to the clip were as shown in Table 1.

(4-2. Multi-layer film)
The left and right ends of the obtained composite film were cut so that the width in the film width direction was 2400 mm. The cut composite film and a masking film made of polyethylene resin were bonded to form a multilayer film. The left and right ends of the multilayer film were cut so that the width in the film width direction was 2260 mm, wound up, and a long film roll was obtained. The obtained film roll was useful in the production of polarizing plates and the like.

[Examples 5 to 6]
Instead of the extrudate obtained in (1-1) of Example 1, the extrudate obtained in (2-1) of Example 2 (Example 5) or (3-1) of Example 3 was used. Except for using the obtained extruded product (Example 6), the same operation as (4-1) of Example 4 was performed to obtain and evaluate a composite film.

[Comparative Example 1]
(C1-1. Composite film)
Except for the following changes, the same operation as in Example 1 was performed, and a composite film was obtained and evaluated.
-Resin [G1] and resin [Z1] were replaced. That is, instead of resin [G1] obtained in Production Example 1, resin [Z1] containing a polymer containing an alicyclic structure was used, and resin [G1] was used instead of resin [Z1].

(C1-2. Stretching of composite film)
The composite film obtained in (C1-1) was used as a pre-stretch film, and an attempt was made to stretch by the same operation as in (4-1) of Example 4, but the film stuck to the clip in the oven. However, stretching could not be performed.

[Comparative Example 2]
(C2-1. Composite film)
Except for the following changes, the same operation as in Example 3 was performed to obtain and evaluate a composite film.
-Resin [G3] and resin [Z1] were replaced. That is, instead of the resin [G3] obtained in Production Example 3, a resin [Z1] containing a polymer containing an alicyclic structure was used, and a resin [G3] was used instead of the resin [Z1].

(C2-2. Stretching of composite film)
The composite film obtained in (C2-1) was used as a pre-stretch film, and an attempt was made to stretch by the same operation as in (4-1) of Example 4, but the film stuck to the clip in the oven. However, stretching could not be performed.

  The results of Examples and Comparative Examples are shown in Tables 1 and 2.

The meanings of the abbreviations in the table are as follows.
Cyclic wG: Ratio (%) of cyclic hydrocarbon group-containing compound hydride unit [I] in hydrogenated block copolymer [G].
Chain wG: Ratio (%) of the chain hydrocarbon compound hydride unit [II] in the hydrogenated block copolymer [G].
Cyclic wE: Ratio (%) of cyclic hydrocarbon group-containing compound hydride unit [I] in block [E] of hydrogenated block copolymer [G].
Chain wE: Ratio (%) of chain hydrocarbon compound hydride unit [II] in block [E] of hydrogenated block copolymer [G].
G1: Resin [G1] produced in Production Example 1.
G2: Resin [G2] produced in Production Example 2.
G3: Resin [G3] produced in Production Example 3.
Z1: A resin containing an alicyclic structure-containing polymer, a heat softening temperature of 128 ° C., one of the product group of “ZEONOR” manufactured by Nippon Zeon.
Z2: a resin containing an alicyclic structure-containing polymer, a heat softening temperature of 136 ° C., one of the product group of “ZEONOR” manufactured by Nippon Zeon.
The symbols A to C relating to Re and Rth are classifications of evaluation of Re and Rth. A: Absolute value of 3 nm or less, B: Absolute value of more than 3 nm and less than 10 nm, C: Absolute value of 10 nm or more.

  As is clear from the results of the examples and comparative examples, the composite film of the example in which the central region (A) and the side region (B) satisfy the requirements of the present invention has less sticking to the clip of the film. The film can be easily manufactured and includes a useful central region (A).

10: Composite film 111: Central region (A)
121: Side region (B)
122: Side region (B)
101: One edge in the width direction of the composite film 102: The other edge in the width direction of the composite film 131: The boundary between the side region (B) and the central region (A)

Claims (9)

A side region (B) of the pair of thermoplastic resins B and a central region (A) of the thermoplastic resin A provided between the side regions (B) of the pair of thermoplastic resins B are provided. ,
The thermoplastic resin A and the thermoplastic resin B are resins containing an alicyclic structure-containing polymer,
The composite film in which the thermoplastic resin A, the thermoplastic resin B, the central region (A) and the side region (B) satisfy the following formulas (1) to (3):
Ea <Eb Formula (1)
Ts [B] −Ts [A] ≧ −10 ° C. Formula (2)
| RthB-RthA | ≧ 1 nm Formula (3)
Where Ea is the tensile elastic modulus of the thermoplastic resin A, Eb is the tensile elastic modulus of the thermoplastic resin B, Ts [A] is the thermal softening temperature of the thermoplastic resin A, and Ts [B] is the thermoplastic resin. The thermal softening temperature of B, RthA represents the thickness direction retardation of the central region (A), and RthB represents the thickness direction retardation of the side region (B). One or both of the thermoplastic resin A and the thermoplastic resin B are:
Two or more polymer blocks [D] per molecule based on a cyclic hydrocarbon group-containing compound hydride unit [I];
One or more polymer blocks [E] per molecule containing as a main component a chain hydrocarbon compound hydride unit [II] or a combination of the unit [I] and the unit [II]
The composite film according to claim 1, comprising a hydrogenated block copolymer [G] containing alicyclic structure-containing polymer.   The cyclic hydrocarbon group-containing compound unit [I] is a structural unit obtained by polymerization of an aromatic vinyl compound, and the chain hydrocarbon compound unit [II] is a structural unit obtained by polymerization of a chain conjugated diene compound. The composite film according to claim 2, wherein The percentage Lb (%) of the ratio of the width direction width LB of the side region (B) to the width direction width L of the entire composite film satisfies the following formula (4). 2. The composite film according to item 1.
0.5% ≦ Lb ≦ 8% (4) It is a manufacturing method of the composite film given in any 1 paragraph of Claims 1-4,
The flow path (B1) of the thermoplastic resin B, the flow path (A) of the thermoplastic resin A, and the flow path (B2) of the thermoplastic resin B were arranged in this order in a direction corresponding to the width direction of the composite film. The manufacturing method including the extrusion process of extruding the said thermoplastic resin A and the said thermoplastic resin B from the extrusion apparatus provided in a state, and obtaining a film-form extrusion molding.   The method for producing a composite film according to claim 5, further comprising a stretching step of stretching the extruded product in one or more directions after the extrusion step.   The method for producing a composite film according to claim 6, wherein the stretching step includes gripping an end portion in the width direction of the extrudate with a clip and stretching in a width direction or an oblique direction.   A polarizing plate provided with the center part area | region (A) of the composite film of any one of Claims 1-4, and a polarizer.   A display apparatus provided with the center part area | region (A) of the composite film of any one of Claims 1-4.

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