TW201637843A - Multilayer film and method for producing same - Google Patents

Abstract

The present invention provides a multilayer film which has high mechanical strength, while having various functions as a multilayer film, and which is able to be processed with high yield and high accuracy in various processing steps. A multilayer film according to the present invention is obtained by alternately laminating layers A which are formed from a crystalline polyester and layers B which are formed from a thermoplastic resin that is different from the crystalline polyester, so that the number of laminated layers is 11 or more in total. This multilayer film is characterized in that the Young's modulus in the orientation axis direction of the multilayer film (the direction in which the Young's modulus is maximum) is 6 GPa or more.

Description

Laminated film and method of manufacturing same

The present invention relates to a laminated film and a method of manufacturing the same.

A thermoplastic resin film, particularly a biaxially stretched polyester film, which has excellent properties such as mechanical properties, electrical properties, dimensional stability, transparency, and chemical resistance, and is also used in magnetic recording materials or packaging materials. It is widely used as a base film in most applications.

On the other hand, among the polyester films, a laminate film in which different resins are alternately laminated is used. In the above-mentioned laminated film, a film having a specific function which is not obtained by a single-layer film can be used, and for example, a tear-resistant film having improved tear strength (see Patent Document 1) and infrared reflection reflecting infrared rays can be used. A film (see Patent Document 2) and a polarizing reflection film having polarized reflection characteristics (see Patent Document 3).

However, in the laminated film as described above, since the structure in which the resin is laminated alternately is employed, the mechanical strength or the dimensional stability tends to be lowered due to the influence of the thickness of the laminate as compared with the film of the single layer. When the mechanical strength or dimensional stability of the laminated film is lowered, for example, when combined with other various films or members, the functional film is subjected to processing such as punching, cutting, coating, and lamination, and the force applied to the film occurs. Deformation or cracking, etc., and the machining accuracy during machining In addition, there is a problem that the yield is lowered, and the optical properties or quality of the obtained film are deteriorated, or there is a problem that a defect occurs due to a dimensional change when actually mounted on a product or the like.

Prior technical literature Patent literature

Patent Document 1 Japanese Patent No. 3960194

Patent Document 2 Japanese Patent No. 4103312

Patent Document 3 Japanese Patent Laid-Open Publication No. 2014-124845

Accordingly, an object of the present invention is to provide a laminated film which can eliminate the above-mentioned problems and which has various functions as a laminated film, and which has high mechanical strength or dimensional stability, and can be produced in various processing steps. Rate/high precision processing, and there is no problem in actual use.

The present invention is directed to the above-mentioned problems, and the laminated film of the present invention is characterized in that it consists of an A layer containing a crystalline polyester and a B layer including a thermoplastic resin different from the crystalline polyester. A laminated film formed of 11 or more layers has a Young's modulus of 6 GPa or more in the direction of the alignment axis (the direction in which the Young's modulus is the largest).

According to a preferred aspect of the laminated film of the present invention, in the polarized Raman spectrum having a beam diameter of 1 μm and a wavelength of 1390 cm ^-1 in the laminated film, the peak intensity I max of the direction in which the reflectance becomes maximum and The ratio I max / I min of the peak intensity I min in the orthogonal direction is 5 or more.

According to a preferred aspect of the laminated film of the present invention, the carboxylic acid component constituting the crystalline polyester contains 90 mol% or more of naphthalene dicarboxylic acid.

According to a preferred aspect of the laminated film of the present invention, a linear expansion coefficient of a temperature of 40° C. or more and 50° C. or less in any one of an alignment axis direction of the laminated film and a direction orthogonal to the alignment axis direction The absolute value is 10 ppm/°C or less.

According to a preferred aspect of the laminated film of the present invention, for a polarizing component parallel to an incident surface including an alignment axis direction of the laminated film, a reflectance at an incident angle of 10° is taken as R1, and The polarizing component perpendicular to the incident surface in the direction of the alignment axis, when the reflectance at an incident angle of 10° is R2, the reflectance at a wavelength of 550 nm satisfies the following formulas (2) and (3);

. R2 (550) ≦ 40%. . . (2)

. R1 (550) ≧ 70%. . . (3)

According to a preferred aspect of the laminated film of the present invention, in the first temperature rise curve of the differential heat measurement (hereinafter referred to as DSC) of the laminated film, the laminated film has a melting peak, and the melting peak temperature thereof is taken as Tm, and It has an exothermic peak in the range of Tm-110 ° C or more and Tm-60 ° C or less.

According to a preferred aspect of the laminated film of the present invention, the ratio of the direction of the alignment axis of the laminated film and the Young's modulus in the direction orthogonal to the same plane is 2 or more.

According to a preferred aspect of the laminated film of the present invention, the laminated film has a heat shrinkage stress at a temperature of 100 ° C in the direction of the alignment axis of 1 MPa or less.

According to a preferred aspect of the laminated film of the present invention, the absolute value of TMA at a temperature of 100 ° C in the direction of the alignment axis of the laminated film is 0.5% or less.

According to a preferred aspect of the laminated film of the present invention, the laminated film is subjected to differential scanning calorimetry (DSC), and the melting peak derived from the thermoplastic resin B is 5 J/g or less.

According to a preferred aspect of the laminated film of the present invention, the A layer and the B layer satisfy the following conditions; A layer: an aromatic polyester containing a dicarboxylic acid component and a diol component as main constituent components, and 80 to 100 mol% of 100 mol% of the dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid, and the diol component 80 to 100 mol% of 100 mol% is ethylene glycol; B layer: an aromatic polyester containing a dicarboxylic acid component and a diol component as main constituent components, and 40 to 75 mol% of the dicarboxylic acid component in 100 mol% is 2,6-naphthalenedicarboxylic acid, 25 to 60 mol% Is a component selected from the group consisting of at least one of isophthalic acid, 1,8-naphthalenedicarboxylic acid, and 2,3-naphthalene dicarboxylic acid, wherein 80 to 100 mol% of the diol component is 100% by weight. Glycol.

According to a preferred aspect of the laminated film of the present invention, the laminated film can be taken up along the alignment axis of the laminated film to form a film roll.

According to a preferred aspect of the film roll of the present invention, the laminated film has a width of 1000 mm or more.

The method for producing a laminated film of the present invention is characterized in that 11 layers or more of unstretched film are laminated by alternately layering A layer containing a crystalline polyester and B layer containing a thermoplastic resin different from the crystalline polyester. A method for producing a laminated film which is extended by 2 to 5 times in the longitudinal direction of the film and which is extended by 2 to 5 times in the film width direction and further extended by 1.3 to 4 times in the longitudinal direction of the film.

According to the present invention, it is possible to obtain a laminated film which has high mechanical strength and dimensional stability, and can be suitably used and used in the processing or use of punching, cutting, coating, and lamination as various functional films. The effect that can be used without any problems during installation.

Since the laminated film of the present invention is a laminated film having a high Young's modulus, it is suitable for various optical films, engineering films, and the like.

[Formation of the Invention]

Next, the laminated film of the present invention and a method for producing the same will be described in detail.

The laminated film of the present invention is a layer (A layer) containing a crystalline polyester (hereinafter sometimes referred to as crystalline polyester A) and a thermoplastic resin different from the crystalline polyester (hereinafter sometimes referred to as thermoplasticity). A layer (layer B) of the resin B) is alternately laminated to form a laminated film of a total of 11 or more layers.

Here, the crystalline polyester A, specifically, is subjected to differential scanning calorimetry (hereinafter sometimes referred to as DSC) according to JIS K7122 (1999), and the resin is heated by 25 ° C at a temperature increase rate of 20 ° C / min ( The temperature rise rate was 20 ° C /min) until the temperature of 300 ° C (1stRUN), and it was kept in the state for 5 minutes, and then it was rapidly cooled at a temperature of 25 ° C or lower, and again at 25 ° C at a temperature increase rate of 20 ° C / min. In the differential scanning calorimetry chart of 2ndRUN obtained by heating up to 300 ° C, the crystal melting heat ΔHm obtained from the peak area of the melting peak was 15 J/g or more. More preferably, the heat of crystal melting is 20 J/g or more, and particularly preferably 25 J/g or more.

Further, the thermoplastic resin B is one which exhibits optical characteristics or thermal characteristics different from those of the crystalline polyester A used in the layer A. Specifically, it means that the refractive index differs by 0.01 or more in either of the two orthogonal directions which are arbitrarily selected in the plane of the laminated film and the direction perpendicular to the surface, or in the DSC, the crystallographic aggregation is exhibited. The melting point or glass transition temperature of ester A is different.

Here, the so-called interactive layering means that the A layer and the B layer are laminated in a regular arrangement in the thickness direction. For example, a laminate is performed in a regular arrangement as indicated by A(BA)n (n is a natural number). As described above, by alternately laminating such resins having different optical properties, it is possible to exhibit dry-reflection of light of a wavelength designed to reflect the relationship between the difference in refractive index of each layer and the layer thickness.

Further, by alternately laminating resins having different thermal characteristics, it is possible to highly control the alignment state of the respective layers at the time of manufacturing the biaxially stretched film, and to control optical characteristics, mechanical properties or heat shrinkage characteristics.

A preferred layered form of the laminated film is a layer B having a crystalline polyester A, a layer B containing a thermoplastic resin B different from the crystalline polyester A, and a crystalline polyester A. The case of the C layer of the thermoplastic resin C different from the thermoplastic resin B. In the case described above, the layer C such as CA(BA)n, CA(BA)nC, and A(BA)nCA(BA)m may be the outermost layer or laminated on the intermediate layer.

In addition, when the number of laminated layers is less than 11 layers, it is difficult to manufacture biaxially stretched films, for example, because of the influence on the physical properties such as film forming properties and mechanical properties of different thermoplastic resin laminates. There is a possibility that a component will be combined and a defect will occur as a product.

On the other hand, in the case of the laminated film of the present invention, the laminated film of a total of 11 or more layers is alternately laminated, compared with the laminated film having a number of layers of less than 11 layers, since each of the thermoplastic resins is uniformly provided. Therefore, film forming properties or mechanical properties can be stabilized. In addition, depending on the number of layers, there is a tendency to suppress the growth of the alignment in the respective layers. For example, in addition to the improvement in the tear strength due to the interfacial tension, it is easy to control the mechanical properties or the heat shrinkage properties, and the display can be imparted. The specific optical properties of the cognac reflector function. The number of layers to be laminated is preferably 100 or more, more preferably 200 or more. When the film is laminated in a layer of 100 or more, light of a wide frequency can be reflected at a high reflectance, and when the layer is formed of 200 or more layers, for example, light of almost all visible light having a wavelength of 400 to 700 nm can be reflected. In addition, there is no upper limit on the number of layers to be laminated. However, as the number of layers increases, the manufacturing cost increases due to the increase in size and complexity of the manufacturing apparatus. Therefore, the actual range of 10,000 layers is practical.

In the laminated film of the present invention, the Young's modulus of the laminated film in the direction of the alignment axis must be 6 GPa or more. Here, the direction of the alignment axis of the laminated film is measured by changing the direction every 10 degrees in the film surface, and the Young's modulus of the film is measured, and the Young's modulus is the largest direction. The Young's modulus is an index indicating the necessary force at the initial deformation of the film, and is applied to the laminated film when the Young's modulus is high and is used in a processing step such as punching, cutting, coating, and lamination, or as a functional film. In addition, deformation can be suppressed, and it is also easy to suppress the processing failure accompanying the deformation of the film or the change in performance at the time of use.

It is preferable that the Young's modulus of the direction of the alignment axis of the laminated film is 8 GPa or more, and more preferably 10 GPa or more. According to the increase in the Young's modulus, the laminated film becomes difficult to be deformed. For example, since the control range of the processing conditions during the processing such as punching, cutting, coating, and lamination becomes large, not only the processing failure but also the obtained product can be improved. The performance is also useful. In order to increase the Young's modulus, as will be described later, in addition to the selection of the resin, a film production method can also be achieved.

In the case of a single layer or a plurality of layers, when the Young's modulus of the laminated film in the direction of the alignment axis is 6 GPa or more, the laminated film tends to be brittle due to the strength of the alignment of the resin, and the handleability is also lowered. Case.

On the other hand, in the case where the layer A comprising the crystalline polyester A and the layer B containing the thermoplastic resin B different from the crystalline polyester A are laminated in a total of 11 or more layers, Even if the Young's modulus is 6 GPa or more, the interfacial tension at the laminate interface or the buffer effect of the B layer containing the thermoplastic resin B may not be used. When the film is applied to a processing step such as punching, cutting, coating, and lamination, or when it is used as a functional film, the effect of suppressing deformation can be obtained when a laminated film is applied with a force.

Further, in the laminated film of the present invention, the aspect ratio of the alignment axis direction of the laminated film and the Young's modulus in the direction orthogonal to the same plane is preferably 2 or more. Even when the ratio of the Young's modulus is increased by simply selecting the resin or the method for producing the film, the Young's modulus is limited in the laminated film having the Young's modulus in the in-plane direction of the laminated film. Since the Young's coefficient depends on the strength of the alignment of the resin constituting the laminated film, how strong the alignment is in the direction in which the Young's modulus is to be increased affects the Young's modulus.

On the other hand, in the processing steps such as punching, cutting, coating, and lamination, particularly in the step of continuously processing using a roll-shaped film, the Young's modulus in the longitudinal direction of the laminated film is improved to stabilize the processing step. The system is effective. Therefore, by setting the ratio of the alignment axis direction of the laminated film and the Young's modulus in the direction orthogonal to the same plane to 2 or more, the Young's modulus on the alignment axis side can be further increased, and the Young's modulus becomes the largest direction. The Young's modulus of the direction of the alignment axis of the laminated film is easily 6 GPa or more. More preferably, the ratio of the direction of the alignment axis of the laminated film and the Young's modulus in the direction orthogonal to the same plane is 3 or more. In this case, the Young's modulus in the direction of the alignment axis of the laminated film is also easily 10 GPa or more. .

In the laminated film of the present invention, in the polarized Raman spectrum having a beam diameter of 1 μm and a wavelength of 1390 cm ^-1 , the ratio of the peak intensity I max in the direction in which the reflectance becomes maximum and the peak intensity I min in the direction orthogonal thereto are I max / I min is preferably 5 or more. Here, the direction in which the reflectance is the largest is the case where the polarizing component is 0° with respect to the incident surface of the laminated film, and the incident angle is 0°, and the reflectance is measured every 10° in the laminated film surface. Indicates the direction in which the reflectance is the maximum.

Further, the peak intensity at the wavelength of 1390 cm ^-1 observed by the polarized Raman spectrum, the peak intensity I max in the direction in which the reflectance becomes maximum, and the peak intensity I in the direction orthogonal thereto by the CNC stretching bond attributed to the naphthalene ring The ratio of min to I max / I min can determine the alignment state of the naphthalene ring. I max / I min at a wavelength of 1390 cm ^-1 is preferably 5.5 or more, more preferably 6 or more.

When the I max / I min at a wavelength of 1390 cm ^-1 is 5 or more, the naphthalene ring is uniformly aligned, and as a result, the Young's modulus can be improved by high alignment. The upper limit of I max / I min at a wavelength of 1390 cm ^-1 is from the alignment of the layer A containing the crystalline polyester A containing naphthalenedicarboxylic acid and the layer B containing the thermoplastic resin B different from the crystalline polyester A. The upper limit is preferably 20, more preferably 10, and particularly preferably 7 or less from the viewpoint of deterioration of interlayer adhesion due to a difference in state or crystallinity. The I max/I min at a wavelength of 1390 cm-1 can be adjusted by the combination of the combination of the resin of the A layer and the B layer and the film forming conditions.

Further, in the laminated film of the present invention, in the polarized Raman spectrum having a beam diameter of 1 μm and a wavelength of 1615 cm ^-1 , the peak intensity I max in the direction in which the reflectance is maximum and the peak intensity I min in the direction orthogonal thereto are A ratio of I max / I min of 4 or more is preferred.

The peak at a wavelength of 1615 cm ^-1 observed by polarized Raman spectroscopy, the peak intensity I max in the direction in which the reflectance becomes maximum, and the peak intensity I in the direction orthogonal thereto by the C=C stretching bond attributed to the benzene ring The ratio of min to I max / I min can be used to determine the alignment state of the benzene ring. I max / I min at a wavelength of 1615 cm ^-1 is preferably 4.5 or more, more preferably 5 or more. The I max/I min at a wavelength of 1615 cm ^-1 is 4 or more, indicating that the benzene ring is uniformly aligned, and as a result, the Young's modulus can be improved by high alignment.

The upper limit of I max / I min at a wavelength of 1615 cm ^-1 is from the alignment of the layer A containing the crystalline polyester A containing naphthalene dicarboxylic acid and the layer B containing the thermoplastic resin B different from the crystalline polyester A. The upper limit is preferably 20 or less, more preferably 10 or less, and particularly preferably 6 or less from the viewpoint of deterioration of interlayer adhesion due to a difference in state or crystallinity. The I max / I min at a wavelength of 1615 cm -1 can be adjusted by the combination of the resin of the A layer and the B layer and the film forming conditions. The most appropriate combination of examples is as described above.

Further, in the laminated film of the present invention, in the polarized Raman spectrum having a beam diameter of 1 μm and a wavelength of 1390 cm ^-1 , the peak intensity I max in the direction in which the reflectance is maximum and the peak intensity I min in the direction orthogonal thereto are The ratio I max / I min is preferably 5 or more.

In the laminated film of the present invention, the absolute value of the linear expansion coefficient of the temperature of 40 ° C or more and 50 ° C or less in the direction of the alignment axis of the laminated film and the direction orthogonal to the direction of the alignment axis must be 10 ppm / Below °C. The coefficient of linear expansion is an index indicating the easy changeability of the film size when the temperature is changed, and is changed according to the absolute value of the thermal expansion coefficient. When it is used in the processing steps such as punching, cutting, coating, and lamination, or when it is used as a functional film, the deformation of the film can be suppressed even when the temperature of the laminated film changes, and the processing failure accompanying the deformation of the film can be easily suppressed. Or performance changes when used.

It is preferable that the absolute value of the linear expansion coefficient is 5 ppm/° C. or less in any of the alignment axis direction of the laminated film and the direction orthogonal to the alignment axis direction. As the absolute value of the thermal expansion coefficient decreases, the deformation of the laminated film with respect to the temperature change becomes small, and for example, the control range of the processing conditions at the time of processing becomes large, so that not only the processing failure but also the performance of the obtained product can be improved. It is also useful to suppress dimensional distortion during actual use. In order to lower the absolute value of the thermal expansion coefficient, as will be described later, in addition to the selection of the resin, a method for producing a film can be achieved.

Further, in the case of the number of layers of a single layer or a plurality of layers, in the direction of the alignment axis of the laminated film, when the absolute value of the coefficient of linear expansion of the temperature of 40 ° C to 50 ° C is 10 ppm / ° C or less, because of the orientation of the resin The strength tends to cause the film to become brittle, and there is also a case where the handleability is lowered. On the other hand, in the case where the layer A including the crystalline polyester A and the layer B containing the thermoplastic resin B different from the crystalline polyester A are laminated in a total of 11 or more layers, Even if the absolute value of the linear expansion coefficient of the temperature of 40 ° C to 50 ° C is 10 ppm / ° C or less, the interfacial tension at the laminated interface or the buffering effect of the B layer containing the thermoplastic resin B can not impair the handleability. Further, when the coefficient of linear expansion is lowered, and when it is used in a processing step such as punching, cutting, coating, and lamination, or as a functional film, the effect of suppressing deformation can be obtained when a laminated film is applied with a force.

Further, in the laminated film of the present invention, the heat shrinkage stress at a temperature of 100 ° C in the direction of the alignment axis of the laminated film is preferably 1 MPa or less. The heat shrinkage stress is an index indicating the magnitude of the force acting in the direction in which the laminated film shrinks when the temperature is changed. By reducing the heat shrinkage stress, deformation can be suppressed when heat is applied to the laminated film during use. Suppresses the performance change of poor processing or laminated film. More preferably, the heat shrinkage stress at a temperature of 100 ° C is 0.5 MPa or less. In this case, thermal deformation of the laminated film can be suppressed even in the processing step or in actual use.

Further, in the laminated film of the present invention, the absolute value of TMA represented by the following formula (1) in the direction of the alignment axis of the laminated film is preferably 0.5% or less at a temperature of 100 °C. In the following formula (1), L and ΔL each indicate the length in the direction of the alignment axis of the laminated film at a temperature of 25 ° C and the displacement of the length of the laminated film when the temperature is changed by the temperature of 25 ° C. TMA is an index indicating the ratio of shrinkage or elongation of the laminated film when the temperature is changed. By reducing the absolute value of TMA, deformation can be suppressed when heat is applied to the laminated film during use, and processing defects or films can be suppressed. Performance changes. More preferably, the absolute value of TMA at a temperature of 100 ° C is 0.5% or less. In this case, thermal deformation of the film can be suppressed even in the processing step or in actual use.

. TMA=|△L/L|×100%. . . (1)

In the present invention, the laminated film can be used as a film roll which is taken up along the alignment axis of the laminated film. As described above, in the processing steps such as punching, cutting, coating, and lamination, in particular, in the step of continuously processing using a roll-shaped film, the Young's modulus in the longitudinal direction of the laminated film is increased. It is effective to stabilize the processing step, and by using the film roll taken up along the alignment axis of the laminated film, the laminated film of the present invention can be used to easily obtain a high-quality product when the product is obtained.

In order to obtain the film roll as described above, the formation angle of the alignment axis direction of the build-up film and the flow direction of the film production step is preferably 10 or less. When the angle between the direction of the alignment axis of the laminated film and the flow direction of the film forming step is 10 or less, the obtained laminated film is continuously wound into a roll shape, and processing steps such as punching, cutting, coating, and lamination are performed. In the step of continuously processing using a roll-shaped film in particular, since the direction of the alignment axis and the flow direction of the processing step become the same, the stabilization of the processing step becomes easy.

Actually, the winding direction of the film roll can be regarded as the flow direction of the film forming step. In the actual product, the forming angle of the direction of the alignment axis of the laminated film and the winding direction of the film roll becomes 10 or less.

In the laminated film of the present invention, the layer A containing the crystalline polyester A is preferably the outermost layer. In this case, since the crystalline polyester A is the outermost layer, it can be produced in the same manner as the crystalline polyester film of a polyethylene terephthalate film or a polyethylene naphthalate film, and a biaxially stretched film can be produced. When the thermoplastic polyester B containing the amorphous resin is used as the outermost layer, the same as the crystalline polyester film, and in the case of obtaining a biaxially stretched film, there are a pair of rolls or a jig. The problem of poor film formation or deterioration of surface properties caused by adhesion of the manufacturing equipment.

As the crystalline polyester A used in the present invention, a polyester obtained by polymerization of a monomer having an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol as a main constituent component is preferably used.

Here, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene dicarboxylic acid, and 1,5-naphthalene dicarboxylic acid; 6-naphthalene dicarboxylic acid, 4,4 ' -diphenyldicarboxylic acid, 4,4 ' -diphenyl ether dicarboxylic acid, 4,4 ' -diphenylindole dicarboxylic acid, and the like. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, and cyclohexanedicarboxylic acid, and the like. These acid components may be used alone or in combination of two or more.

In particular, as the carboxylic acid component constituting the crystalline polyester A used in the laminated film of the present invention, it is preferable to use terephthalic acid and 2,6-naphthalene from the viewpoint of exhibiting a high refractive index and increasing the Young's modulus. Dicarboxylic acid. Since terephthalic acid or 2,6-naphthalene dicarboxylic acid contains an aromatic ring having high symmetry, it is easy to combine both a high refractive index and a high Young's modulus by performing alignment and crystallization. In particular, when the carboxylic acid component constituting the crystalline polyester A contains 2,6-naphthalene dicarboxylic acid, a high Young's modulus can be achieved by increasing the volume ratio of the aromatic ring, and it can be obtained industrially. As a low-cost product.

Further, more preferably, the carboxylic acid component constituting the crystalline polyester contains 80 mol% or more of 2,6-naphthalene dicarboxylic acid. When 80% by mole or more of naphthalene dicarboxylic acid is contained, in the production of the laminated film, by performing stretching and heat treatment, the alignment crystallization can be easily performed, and the high Young's modulus can be easily performed.

Further, examples of the diol component include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, neopentyl glycol, 1,3-butylene glycol, and 1,4-butanediol. , 5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, Three B A diol, a polyalkylene glycol, a 2,2-bis(4-hydroxyethoxyphenyl)propane, an isosorbate, a spiroglycerol or the like. Among them, ethylene glycol is a preferred component from the viewpoint of ease of polymerization.

Here, the main component means 80 mol% or more of the diol component. More preferably, it is 90 mol% or more. These diol components may be used alone or in combination of two or more. It is also possible to locally copolymerize an oxo acid or the like of a hydroxybenzoic acid or the like.

As the thermoplastic resin B used in the present invention, a chain polyolefin such as polyethylene, polypropylene or poly(4-methylpentene-1) can be used; ring-opening displacement polymerization and addition polymerization of norbornene , an alicyclic polyolefin as an addition copolymer with other olefins; polyamide, aramid, polymethyl methacrylate such as nylon 6, nylon 11, nylon 12, nylon 66, etc. , polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglycolic acid, polystyrene, styrene copolymerized polymethyl methacrylate Ester, polycarbonate; polytrimethylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polylactic acid, poly Polyesters such as butyl succinate; polyether oxime, polyether ether ketone, modified polyphenylene ether, polyphenylene sulfide, polyether phthalimide, poly phthalimide, polyarylate, tetrafluoroethylene resin, A trifluoroethylene resin, a vinyl trifluoroethylene resin, a tetrafluoroethylene-hexafluoropropylene copolymer, and polyvinylidene fluoride.

Among these, in addition to the viewpoints of strength, heat resistance, transparency, and versatility, polyester is preferably used from the viewpoint of adhesion to the crystalline polyester A used in the layer A and the layering property. These may be used, whether they are copolymers or mixtures.

In the laminated film of the present invention, when the thermoplastic resin B is a polyester, it is preferred to use a monomer which contains an aromatic dicarboxylic acid component and/or an aliphatic dicarboxylic acid component and a diol component as main constituents. The resulting polyester is polymerized. Here, as the aromatic dicarboxylic acid component, the aliphatic dicarboxylic acid component, and the diol component, those exemplified in the crystalline polyester A can be suitably used.

In the laminated film of the present invention, the thermoplastic resin B is preferably an aromatic polyester having an aromatic dicarboxylic acid component and a diol component as main constituent components. In particular, 40 to 75 mol% of 100 mol% of the dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid, and 25 to 60 mol% is selected from the group consisting of isophthalic acid, 1,8-naphthalenedicarboxylic acid, and 2,3- The component in the group of naphthalene dicarboxylic acid, 80 to 100 mol% of the diol component in 100 mol% is a more preferable aspect.

Isophthalic acid, 1,8-naphthalenedicarboxylic acid, and 2,3-naphthalene dicarboxylic acid have an effect of bending a molecular chain depending on the molecular skeleton thereof, and as a result, the crystallinity or elongation of the thermoplastic tree B can be made. The alignment is declining. As a result, it is possible to suppress an increase in the refractive index accompanying the alignment crystallization of the B layer in the production of the stretched film, and it is possible to make a difference in refractive index from the layer A containing the crystalline polyester A (in the case of the polarized reflection property, the layer A is The refractive index difference of the alignment axis is easily generated. As a result, higher optical characteristics can be exhibited particularly when exhibiting polarized reflection characteristics.

In order to obtain a laminated film having a dry-reflecting function, as the thermoplastic resin B, an amorphous resin is also preferable. Compared with the crystalline resin, the amorphous resin is less likely to cause alignment when the biaxially stretched film is produced, and thus it is possible to suppress the accompanying inclusion of the thermoplastic resin B. The refractive index of the alignment crystallization of the layer B is increased, and the difference in refractive index from the layer A containing the crystalline polyester A can be easily produced. This effect is remarkable particularly when a heat treatment step is provided at the time of producing the stretched film.

In the alignment resulting from the stretching step, the alignment generated in the layer B can be completely alleviated in the heat treatment step, and the refractive index difference from the layer A containing the crystalline polyester can be maximized.

Here, the term "amorphous resin" refers to a temperature (1stRUN) at which the resin is heated from 25 ° C (temperature up rate 20 ° C / min) to 300 ° C at a temperature increase rate of 20 ° C / min according to JIS K7122 (1999). After the state was maintained for 5 minutes, it was then cooled to a temperature of 25 ° C or lower, and then rapidly cooled at room temperature by a temperature increase rate of 20 ° C /min to 300 ° C to obtain a 2nd RUN differential scanning calorimetry chart. The resin having a crystal melting heat ΔHm of 5 J/g or less, which is obtained by the peak area of the melting peak, is more preferably a resin which does not exhibit a peak corresponding to crystal melting.

Moreover, in order to obtain a laminated film having a dry-reflecting function, it is preferable to use a crystalline resin having a melting point lower than the melting point of the crystalline polyester A by 20 ° C or more as the thermoplastic resin B. In this case, in the heat treatment step, by performing heat treatment at a temperature between the melting point of the thermoplastic resin B and the melting point of the crystalline polyester A, the heat treatment step can be completely alleviated, and the crystalline polyester can be contained. The refractive index difference of the A layer of A is maximized. The difference between the melting points of the crystalline polyester A and the thermoplastic resin B is preferably 40 ° C or higher. In this case, since the selection range of the temperature in the heat treatment step is widened, the alignment of the thermoplastic resin B can be more easily promoted or the alignment of the crystalline polyester can be controlled.

As a preferable combination of the crystalline polyester A and the thermoplastic resin B, the absolute value of the difference between the SP values of both is preferably 1.0 or less. When the absolute value of the difference of the SP values is 1.0 or less, peeling between layers of the A layer and the B layer is less likely to occur. More preferably, the crystalline polyester A and the thermoplastic resin B contain a combination of the same basic skeleton.

The basic skeleton here is a repeating unit constituting a resin. For example, as the crystalline polyester A, a polyethylene naphthalate containing only a 2,6-naphthalene dicarboxylic acid or a carboxylic acid component containing 80% or more of a 2,6-naphthalenedicarboxylic acid is used. When the polyethylene naphthalate copolymer is used as the main component, as the thermoplastic resin B, a relatively amorphous polyethylene naphthalate copolymer or a crystalline polyester A having a lower melting point is used. The polyethylene naphthalate copolymer is preferred.

Further, in order to obtain a laminated film having a dry-reflecting function, the glass transition temperature of the thermoplastic resin B is preferably 10 ° C or more lower than the glass transition temperature of the crystalline polyester A. In this case, in the stretching step, when the most suitable elongation temperature is taken in order to extend the crystalline polyester, since the alignment of the thermoplastic resin B is not progressed, the refraction of the layer A containing the crystalline polyester can be made. The rate difference becomes larger. More preferably, the glass transition temperature of the thermoplastic resin B is lower than the glass transition temperature of the crystalline polyester A by 20 ° C or more.

In order to obtain a suitable method for producing a laminated film of the present invention to be described later, the alignment crystallization of the thermoplastic resin B may progress easily, and the desired dry-reflecting function may not be obtained, but by heat The glass transition temperature of the plastic resin B is lower than the glass transition temperature of the crystalline polyester A by 20 ° C or more, and the alignment crystallization can be suppressed.

Further, in the thermoplastic resin, various additives such as an antioxidant, a heat stabilizer, a weathering stabilizer, an ultraviolet absorber, an organic slip agent, a pigment, a dye, an organic or an additive may be added without deteriorating the properties. Inorganic fine particles, fillers, antistatic agents, and nucleating agents.

In the laminated film of the present invention, for a polarizing component parallel to an incident surface including an alignment axis direction of the laminated film, a reflectance at an incident angle of 10° is taken as R1, and for an alignment axis with respect to the laminated film and the laminated film. When the reflectance perpendicular to the incident surface in the direction is R2 at an incident angle of 10°, the reflectance at a wavelength of 550 nm satisfies the following formulas (2) and (3). By satisfying the following formulas (2) and (3), it is possible to impart polarization reflection characteristics that reflect either of the polarized light and penetrate the other polarized light.

In order to obtain a film satisfying the following formula (2), the film may be adjusted by a combination of a resin having a difference in refractive index between the layer A and the layer B in the direction of the alignment axis of the laminated film of 0.02 or less, more preferably 0.01 or less. It is 0.005 or less. In addition, in order to obtain a film satisfying the following formula (3), a combination of a resin having a refractive index difference between the A layer and the B layer in the direction orthogonal to the alignment axis direction of the laminated film of 0.08 or more can be selected and formed into a film. The condition is adjusted to be more preferably 0.1 or more, and particularly preferably 0.15 or more. An example of the most suitable combination thereof is as described above.

. R2 (550) ≦ 40%. . . (2)

. R1 (550) ≧ 70%. . . (3).

In the laminated film of the present invention, in the first heating curve of the DSC, the laminated film has a melting peak Tm and a melting peak temperature thereof The range of Tm-110 ° C or more and Tm-60 ° C or less has an exothermic peak. On the premise of exhibiting the above-described polarization characteristics, the refractive index control of each layer becomes important, and it is important to control the alignment and crystallinity. In the control thereof, the layer A containing the crystalline polyester A can be made to have a high refractive index in one direction, so that the refractive index difference between the alignment direction and the vertical direction thereof can be made large. On the other hand, the B layer must be identical to either of the refractive indices of the A layer (mainly in a direction in which the refractive index is low), and the refractive index difference from the other side (mainly in a direction in which the refractive index is high) becomes large, and the B layer is controlled. Orientation or crystallinity is important.

The inventors of the present invention have carefully studied and found that, as an index of the B-layer control, in the first heating curve of the DSC, the laminated film has a melting peak Tm and a melting peak temperature Tm-110 ° C or more Tm-60 ° C. The following ranges have an exothermic peak for high optical properties.

This exothermic peak is an exothermic peak which shows the crystallization of the B layer, and is an index of the orientation and crystallinity of the B layer. When the exothermic peak is not present, the B layer undergoes crystallization in the film formation step, or the crystallinity is extremely low. Therefore, the relationship with the refractive index of the layer A is not in the desired range, and the optical characteristics are deteriorated.

In addition, even if the exothermic peak is present and exceeds Tm-110 ° C or more and Tm-60 ° C or less, the relationship between the refractive index of the A layer and the A layer is exhibited because the B layer is excessively aligned and exhibits anisotropy or crystallinity is extremely low. Not in the required range, and optical properties are degraded. Therefore, in the laminated film of the present invention, in order to obtain high optical characteristics, it is necessary to have an exothermic peak in a range of Tm - 110 ° C or more and Tm - 60 ° C or less.

As a method of producing a laminated film having an exothermic peak at a Tm-110 ° C or higher and a Tm-60 ° C or lower, it is possible to make the A layer and the B layer Preferably, in the manufacturing method described later, the temperature, the magnification, and the stretching speed of the stretching step are preferably in a preferred range. These methods are also suitable for combining multiple.

In the laminated film of the present invention, the heat release amount of the exothermic peak is preferably 0.1 J/g or more and 10 J/g or less. The calorific value is preferably 0.5 J/g or more and 5 J/g or less, and particularly preferably 1.5 J/g or more and 4 J/g or less. When the exothermic heat exceeds Tm-110°C or more and Tm-60°C or less, the B layer will be excessively aligned, exhibiting anisotropy, or the crystallinity becomes extremely low, and the relationship with the refractive index of the A layer is not in the required range. Optical characteristics are degraded. In the laminated film of the present invention, high optical characteristics can be obtained by setting the heat release amount of the exothermic peak to 0.1 J/g or more and 10 J/g or less.

In the laminated film of the present invention, the melting peak temperature Tm is preferably 255 ° C or higher. The melting peak temperature is more preferably 258 ° C or higher. In order to satisfy the range of the melting peak temperature, a resin which is also preferably in the above-mentioned resin is selected, whereby the optical properties can be improved and the film having high heat resistance can be obtained.

Next, a preferred method for producing the laminated film of the present invention will be described below.

In addition, the laminated structure of the laminated film used in the present invention can be easily realized by the same method as that described in paragraphs [0053] to [0063] of JP-A-2007-307893.

First, the crystalline polyester A and the thermoplastic resin B are prepared in the form of pellets or the like. The pellets can be supplied to separate extruders after being dried in hot air or under vacuum as needed. In the extruder, the resin that is heated and melted is homogenized by a gear pump or the like, and is passed through The filter or the like removes foreign matter or a modified resin or the like. These resins are fed into a multilayer lamination device.

As the multilayer laminated device, a multiple branch pipe mold, a feed head, a static mixer, or the like can be used. However, in order to efficiently obtain the constitution of the present invention, it is preferable to use a feed head having 11 or more fine slits. By using the feed head as described above, the apparatus does not become extremely large, and therefore foreign matter due to thermal deterioration is small, and even when the number of layers is extremely large, high-precision lamination can be achieved. Moreover, the stacking accuracy in the width direction is also remarkably improved as compared with the prior art. Further, in this apparatus, since the thickness of each layer can be adjusted by the shape (length, width) of the slit, an arbitrary layer thickness can be achieved.

Then, the laminated sheet discharged from the mold is extruded and cooled and solidified on a cooling body such as a casting drum to obtain a cast film. In this case, an electrode such as a wire, a belt, a needle, or a knife is used, and the discharged sheet is adhered to the cooling body by electrostatic force, and is preferably cooled and solidified. Further, as a method of adhering the discharged sheet to the cooling body, a method of blowing air from a slit-like, dot-like or planar device and using a roll is also preferable.

The cast film obtained as described above is preferably biaxially stretched. Here, the biaxial stretching means that the film is extended in the longitudinal direction and the width direction.

Further, as a method for obtaining a suitable biaxial stretching of the laminated film of the present invention, it is necessary to extend at a magnification of 2 to 5 times in the longitudinal direction of the film, and then extend 2 to 5 times in the film width direction, and again The long side of the film extends 1.3 to 4 times. The details are described below.

First, the obtained cast film was extended in the longitudinal direction. The extension of the longitudinal direction is usually carried out using the difference in circumferential velocity of the rolls. This extension can be carried out in one stage, and it is also possible to carry out multiple stages using a plurality of roller pairs. The magnification as the elongation varies depending on the type of the resin, but it is preferably 2 to 5 times. The purpose of extending the first time in the longitudinal direction is to provide a necessary minimum alignment for the purpose of improving the uniform elongation in the subsequent extension of the film in the width direction. Therefore, when the stretching ratio is increased by a factor of more than 5 times, a film having a sufficient stretching ratio cannot be obtained when extending in the width direction of the film to be described later and re-stretching in the longitudinal direction after the step. Case. Further, when the stretching ratio is less than 2 times, it is impossible to provide the necessary minimum alignment during stretching, and there is a case where the thickness is uneven in the longitudinal direction of the film and the quality is lowered. Further, as the stretching temperature, the glass transition temperature to the glass transition temperature of the crystalline polyester A constituting the laminated film is preferably +30 °C.

The uniaxially stretched film obtained as described above may be subjected to surface treatment such as corona treatment, flame treatment, or plasma treatment as needed, and may be provided with smoothness, easy adhesion, and antistatic property by wire coating. function.

Next, the uniaxially stretched film is extended in the width direction. In the width direction, a tenter is usually used, and both ends of the film are held by a jig, and are conveyed and extended in the width direction. The magnification as the elongation varies depending on the type of the resin, but is usually 2 to 5 times. The purpose of the extension in the width direction is to provide a necessary minimum alignment for the purpose of imparting high elongation to the subsequent extension of the film in the longitudinal direction. Therefore, the case where the stretching ratio becomes a magnification larger than 5 times is followed by In the case where the film is re-extending in the longitudinal direction of the film, there is a case where a film having a sufficient stretching ratio cannot be obtained. Moreover, when the stretching ratio is less than 2 times, there is a case where the thickness is uneven in the film width direction at the time of stretching, and the quality is lowered. Further, the stretching temperature is preferably between the glass transition temperature of the crystalline polyester A constituting the laminated film, the glass transition temperature + 30 ° C, or the glass transition temperature to the crystallization temperature of the crystalline polyester.

Next, the obtained biaxially stretched film was again extended toward the long side. The extension of the pair of long sides is usually carried out using the difference in circumferential speed of the rolls. This extension can be carried out in one stage, or multiple stages can be carried out using a plurality of roll pairs. The magnification of the extension varies depending on the type of the resin, but it is preferably 1.3 to 4 times. The purpose of extending the second time in the longitudinal direction is to strongly align the direction of the longitudinal direction of the film as much as possible. If the longitudinal direction is extended again, the resin will strongly align, and as a result, the laminated film can be made. The coefficient of linear expansion of the Young's modulus in the direction of the alignment axis is 6 GPa or more, or the direction in which the Young's modulus is maximized (the direction of the alignment axis of the laminated film) is 10 ppm/° C. or less. In particular, the higher the stretching ratio in the longitudinal direction, the higher the Young's modulus, or the linear expansion coefficient can be suppressed, and the Young's modulus becomes 10 GPa or more, and the absolute value of the linear expansion coefficient of 40 ° C or more and 50 ° C or less becomes It is also easy to be 5 ppm/°C or less. Further, the stretching temperature is preferably such that the glass transition temperature to the glass transition temperature of the crystalline polyester A constituting the laminated film is +80 °C.

As described above, in order to impart planarity and dimensional stability to the biaxially stretched film, heat treatment at a temperature equal to or higher than the melting point in the tenter is preferred. By performing heat treatment, it is possible to promote alignment crystallization and obtain an effect of increasing the Young's modulus, accompanied by alignment The promotion of crystallization also enhances the dimensional stability. As a result, in any one of the direction in which the Young's modulus is the largest (the direction of the alignment axis of the laminated film) and the direction orthogonal to the direction of the alignment axis of the laminated film, 40 can be used. The absolute value of the linear expansion coefficient at a temperature of from ° C to 50 ° C is 5 ppm / ° C or less. In addition, the heat shrinkage stress at a temperature of 100 ° C in the direction of the alignment axis may be 1 MPa or less, and the absolute value of TMA at a temperature of 100 ° C in the direction of the alignment axis may be 0.5% or less. After the heat treatment as described above, the mixture was uniformly cooled, and then cooled to room temperature and taken up. Further, if necessary, after the heat treatment, the relaxation treatment or the like may be performed during the slow cooling.

The laminated film obtained by the above-described production method can be used as a laminated film having high Young's modulus and having polarized reflection characteristics satisfying the above formulas (2) and (3). When the film is stretched in the longitudinal direction of the second film, the alignment of the layer A containing the crystalline polyester A can be made stronger in the longitudinal direction of the film, and as a result, the refractive index in the longitudinal direction of the film and A difference in refractive index in the width direction of the film orthogonal to the longitudinal direction of the film occurs. Further, as the thermoplastic resin B, an amorphous resin or a combination of the crystalline polyester A and the thermoplastic resin B which can alleviate the difference in the glass transition temperature/melting point of the alignment in the stretching step and the heat treatment step may be selected. Thereby, the alignment of the thermoplastic resin B can be suppressed, and the polarized reflection characteristics can be imparted.

(Method for measuring characteristics and method for evaluating effects)

The method for measuring the characteristics of the present invention and the method for evaluating the effects are as follows.

(1) Number of layers:

The layer structure of the laminated film was determined by observing a sample cut out using a microtome by a transmission electron microscope (TEM). In other words, a cross-sectional photograph of the film was taken under the conditions of an acceleration voltage of 75 kV using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), and the layer constitution and the thickness of each layer were measured. According to the situation, in order to improve the contrast, a dyeing technique using RuO ₄ or OsO ₄ or the like is utilized. Further, the thickness of the thinnest layer (thin film layer) among all the layers contained in one image is matched, and when the thickness of the film layer is less than 50 nm, the observation is performed at a magnification of 100,000 times in the thickness of the film layer. When it is 50 nm or more and less than 500 nm, observation is performed by the expansion magnification of 40,000 times, and when it is 500 nm or more, observation is performed by the expansion magnification of 10,000 times.

(2) Calculation method of layer thickness and number of layers:

The TEM photograph image obtained in the above item (1) was included in an image size of 720 dpi using a scanner (CANOSCAN D1230U manufactured by Canon Co., Ltd.). Save the image in a bitmap file (BMP) or compressed image file (JPEG) on a personal computer, and then use the image processing software Image-Pro Plus ver.4 (seller: Planetron) The file is imaged. In the image analysis processing, the relationship between the average brightness of the region sandwiched between the thickness direction position and the width direction is read as a numerical data in a vertical Thick Profile Mode.

Using the table calculation software (Excel 2000), with respect to the position (nm) and brightness data, after the data is taken in the sampling step 2 (thinning 2), the numerical processing of the 5-point moving average is performed. Furthermore, the obtained periodic luminance change data is differentiated, and the maximum value and the minimum value of the differential curve are read by using a VBA (Visual Basic for Applications) program. The value is calculated as the layer thickness of one layer from the interval between the region where the brightness is extremely large and the region where the brightness is extremely large, and the layer thickness is calculated. This operation was performed for each photograph, and the layer thickness and the number of layers of all the layers were calculated.

(3) Young's coefficient:

The laminated film was cut into an elongated rectangle having a length of 150 mm and a width of 10 mm as a sample. A tensile tester (Tensilon UCT-100 manufactured by ORIENTEC) was used, and the distance between the initial stretching chucks was set to 50 mm, and the stretching speed was set to 300 mm/min, and the tensile test was performed. The measurement was carried out in an environment of room temperature 23 ° C and a relative humidity of 65%, and the Young's modulus was obtained from the obtained load-strain curve. The measurement was performed 5 times for each sample, and the average value was evaluated.

(4) Direction of the alignment axis of the laminated film:

The Young's modulus of the laminated film was measured by changing the direction every 10 degrees in the film surface, and the direction in which the Young's modulus was the largest was taken as the direction of the alignment axis of the laminated film.

(5) Linear expansion coefficient:

The laminated film was cut into a slender rectangle having a length of 25 mm and a width of 4 mm in the direction of the alignment axis, and was used as a sample. Using a TMA tester (TMA/SS6000 manufactured by Seiko Instruments), the distance between the initial stretching chucks was set to 15 mm, the tensile tension was maintained at 29.4 mN, and the temperature inside the test machine was raised from 25 ° C to 5 ° C / min until 150. The temperature of °C was measured by TMA for the direction of the alignment axis of the laminated film. The linear expansion coefficient of the temperature of 40 ° C to 50 ° C was obtained from the obtained TMA-temperature curve. The coefficient of linear expansion is determined from the difference between the value of TMA and the temperature and the temperature to be measured ± 5 ° C.

(6) Thermal shrinkage stress:

The laminated film was cut into a slender rectangle having a length of 25 mm and a width of 4 mm in the direction of the alignment axis, and was used as a sample. Using a TMA tester (TMA/SS6000 manufactured by Seiko Instruments), the distance between the tension chucks was fixed at 15 mm, and the temperature inside the test machine was raised from 25 ° C to 5 ° C / min to 150 ° C for the alignment axis of the laminated film. The direction is determined by the heat shrinkage stress. The heat shrinkage stress was obtained from the obtained stress-temperature curve.

(7) TMA:

The laminated film was cut into a slender rectangle having a length of 25 mm and a width of 4 mm in the direction of the alignment axis, and was used as a sample. Using a TMA tester (TMA/SS6000 manufactured by Seiko Instruments), the distance between the initial stretching chucks was set to 15 mm, the tensile tension was maintained at 29.4 mN, and the temperature inside the test machine was raised from 25 ° C to 5 ° C / min until 150. The temperature of °C was measured by TMA for the direction of the alignment axis of the laminated film. The TMA was determined from the obtained TMA-temperature curve.

(8) Measurement of reflectance and transmittance with respect to incident light having a polarizing component:

The center of the alignment axis direction on the line segment in which the length of the sample from the alignment axis direction was the largest was cut out to be 5 cm × 5 cm. The basic structure of the integrating sphere attached to the spectrophotometer (U-4100 Spectrophotomater) manufactured by Hitachi, Ltd. was used, and the sub-whiteboard of alumina attached to the apparatus was used as a reference. The sample was placed in the vertical direction of the alignment axis of the laminated film and placed behind the integrating sphere. Further, a polarizer made of an attached Glan Taylor company was placed, and a linearly polarized light having a polarization component of 0 and 90° was incident thereon, and a reflectance of a wavelength of 250 to 1,500 nm was measured.

The measurement conditions are as follows. The slit was set to 2 nm (visible light)/automatic control (infrared light), the gain was set to 2, and the scanning speed was measured at 600 nm/min to obtain a reflectance of azimuth angle of 0 to 180 degrees. When the reflection of the sample was measured, the interference disappeared due to the reflection from the back surface, so it was blackened with Magic Ink (registered trademark).

Further, the sample cut in the same manner was not blackened, and the transmittance was measured in the same manner. From the obtained transmittance data, the extinction ratio at a wavelength of 550 nm was obtained from the following equation.

. Extinction ratio = T2/T1

(here, T1 indicates a transmittance of an incident angle of 0° with respect to a polarization component parallel to an incident surface including an alignment axis direction of the laminated film, and T2 indicates a vertical direction with respect to an incident surface with respect to an alignment axis direction of the laminated film. The polarization component, the transmittance of the incident angle of 0 °.)

(9) Peak intensity ratio of polarized Raman spectrum I max/I min:

The polarized Raman spectrum was measured using a Raman spectroscopic device, T-64000 manufactured by Jovin Yvon. In the laminated film, the direction in which the reflectance determined in the above item (4) is the largest is taken as I max , and the direction orthogonal thereto is taken as I min , and the cut surface in each direction is the measurement surface, and the section is cut by the slicer. . The polarized Raman spectrum was measured as a parallel condition when the polarization axis of the laser was aligned with the transmission axis of the film, and the case where the thickness direction of the laminated film was aligned was measured as a vertical condition. In the measurement, the measurement was performed at three points in the center of each layer, and the average value was used as the measured value. The detailed measurement conditions are as follows.

. Measurement mode: micro Raman

. Object lens: ×100

. Beam diameter: 1μm

. Cross seam: 100μm

. Light source: Ar+ laser / 514.5nm

. Laser power: 15mW

. Diffraction grating: Spectrograph 600gr/mm

. Dispersion: Single 21Å/mm

. Seam: 100μm

. Detector: CCD/Jobin Yvon 1024×256.

The peak intensity ratio of the polarization Raman spectrum of the wavelength 1390 cm ^-1 and the wavelength of 1615 cm ^-1 is I max / I min , and the peak intensity of 1390 cm ^-1 of the CN stretching ring derived from the naphthalene ring obtained by the measurement of the polarized Raman spectrum. And the peak intensity of 1615 cm ^-1 of the C=C stretching bond derived from the benzene ring is calculated from the peak intensity of the sample in the I max direction of the measurement surface and the peak intensity of the sample in the I min direction. ratio.

(10) melting enthalpy and glass transition temperature:

The self-measured laminated film was sampled, and the DSC curve of the measured sample was measured by differential thermal analysis (DSC) according to JIS-K-7122 (1987). The test was carried out by raising the temperature from 20 ° C / min to a temperature of 290 ° C at 25 ° C, and measuring the melting enthalpy and the glass transition temperature at this time. The device used and the like are as follows.

. Device: "Robot DSC-RDC220" made by Seiko Electronics Industry Co., Ltd.

. Data analysis "disk session SSC/5200"

. Sample quality: 5 mg.

(11) Processability:

The roll-shaped film was introduced into a punching machine, and a rectangular mold having a length of 500 mm and a width of 95% with respect to the film width was punched out. Moreover, the punching interval in the longitudinal direction is set to 40 mm. The following A, B, and C evaluations were performed. Take A and B as qualified.

A: The film is not broken, can be continuously conveyed, and can be processed.

B: Although the film causes partial cracking, it can continuously convey the long side direction and can be processed continuously.

C: The film is completely broken, and the long side direction cannot be continuously processed.

(12) Installation test:

The laminated film to be a sample was cut out from the position at the center of the film width direction by a length of 1450 mm in the longitudinal direction and a width of 820 mm in the width direction. Next, in the 32-type liquid crystal TV LHD32K15JP backlight manufactured by HISENSE JAPAN Co., Ltd., it is arranged in the order of 50% diffusion plate, microlens sheet, polarizing reflector, and polarizing plate, and based on the temperatures of 50 ° C and 85 ° C. The planarity of the polarizing reflector after the 12-hour heat resistance test was visually evaluated.

The evaluation of the planarity was judged by the following A, B and C. A is qualified.

A: No temperature problem at 50 ° C and 85 ° C

B: There is an appearance problem at a temperature of 50 °C.

(13) Naphthalene dicarboxylic acid content:

The layer A containing the crystalline polyester of the laminated film was dissolved in deuterated hexafluoroisopropanol (HFIP) or a mixed solvent of HFIP and deuterated chloroform, and composition analysis was carried out by using 1H-NMR and 13C-NMR.

[Examples] (Example 1)

As the crystalline polyester A, 2,6-polyethylene naphthalate (PEN) having a melting point of 266 ° C and a glass transition temperature of 122 ° C was used. Further, as the thermoplastic resin B, an amorphous resin having no melting point is used, and 25 mol% of 2,6-naphthalenedicarboxylic acid spiro glycerin having a glass transition temperature of 103 ° C and 25 mol% of terephthalic acid, and Copolymerized PEN (copolymerized PEN1) copolymerized with 50 mol% of ethylene glycol.

The prepared crystalline polyester A and the thermoplastic resin B were each placed in two uniaxial extruders, and melted and kneaded at a temperature of 290 °C. Then, the crystalline polyester A and the thermoplastic resin B were respectively placed in a FSS-type disc filter, and then they were measured by a gear pump, and were joined by a laminating device having 11 slits to obtain a thickness direction. An 11-layer laminate is alternately laminated. The method of forming a laminate can be carried out in accordance with the method described in paragraphs [0053] to [0056] of JP-A-2007-307893.

Here, the length and interval of the slit are all fixed. The obtained laminated body had six layers of the crystalline polyester A and five layers of the thermoplastic resin B, and had a laminated structure in which the layers were alternately laminated in the thickness direction. Moreover, the value of the length of the ferrule lip in the width direction of the ferrule inside the ferrule divided by the length in the film width direction of the inlet portion of the ferrule was 2.5. The resulting cast film had a width of 600 mm.

The obtained cast film was heated at a roll set at a temperature of 120 ° C, and then stretched 3.0 times in a longitudinal direction of the film at a temperature set at 135 ° C, and then temporarily cooled. Will be obtained as described above The uniaxially stretched film was guided to a tenter, preheated by hot air at a temperature of 115 ° C, and then extended by 3.0 times in the film width direction at a temperature of 135 ° C to obtain a biaxially stretched film as a film roll. The biaxially stretched film obtained here has a width of 1500 mm.

Further, the biaxially stretched film was heated at a temperature of 120 ° C, and then stretched 3.0 times in the longitudinal direction of the film at a temperature set to 160 ° C, and the ends of the film were conditioned to obtain the target. A film roll having a film width of 1000 mm and a length of 200 m.

The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C) in the MD direction. Further, it is shown that the dry ray reflection characteristics are different from those of the crystalline polyester A and the thermoplastic resin B. The laminated film of the present invention can also be suitably used in the processing of a product or in actual use.

(Example 2)

A laminate film was obtained in the same manner as in Example 1 except that a laminate having a number of slits was used.

The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C) in the longitudinal direction of the film as in Example 1. Further, the dry-ray reflection characteristics derived from the refractive indices different from those of the crystalline polyester A and the thermoplastic resin B were exhibited, and the high-polarization reflection characteristics were also exhibited as compared with Example 1. The laminated film can be continuously produced with high precision and stability during processing of the product, and can be used without any problem in actual use.

(Example 3)

A laminate film was obtained in the same manner as in Example 1 except that a laminate having a number of slits was used.

The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C) in the MD direction as in Example 1. Further, the dry-ray reflection characteristics derived from the refractive indices different from those of the crystalline polyester A and the thermoplastic resin B are exhibited, and the high-polarization reflection characteristics are also exhibited as compared with the second embodiment, and the level can be used as a polarizing reflection member. The laminated film can be continuously produced with high precision and stability during processing of the product, and can be used without any problem in actual use.

(Example 4)

A laminate film was obtained in the same manner as in Example 1 except that the number of slits was 801. The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C) in the MD direction as in Example 1. Moreover, the dry-ray reflection characteristics derived from the refractive indices different from those of the crystalline polyester A and the thermoplastic resin B are exhibited, and the high-polarization reflection characteristics are also exhibited as compared with the third embodiment, and the polarized reflection member has a very high performance. The laminated film can be continuously produced with high precision and stability during processing of the product, and can be used without any problem in actual use.

(Example 5)

A laminate film was obtained in the same manner as in Example 4 except that the magnification of the biaxially stretched film was further increased to 2.5 times in the longitudinal direction of the film. The obtained laminated film system showed the contents shown in Table 1. Sex, showing high Young's coefficient and low linear expansion coefficient (40~50 °C). Further, in the same manner as in the fourth embodiment, high polarization reflection characteristics were exhibited, and the polarizing reflection member was extremely high in performance. The laminated film can be continuously produced with high precision and stability during processing of the product, and can be used without any problem in actual use.

(Example 6)

A laminate film was obtained in the same manner as in Example 4 except that the magnification of the biaxially stretched film was further increased to 2.2 times in the longitudinal direction of the film. The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C). The laminated film can be continuously produced when the product is processed under specific conditions, and can be used without any problem in actual use.

(Example 7)

A laminate film was obtained in the same manner as in Example 4 except that the magnification of the biaxially stretched film was further increased to 2.0 times in the longitudinal direction of the film. The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C). The laminated film can be continuously produced when the product is processed under specific conditions, and can be used without any problem in actual use.

(Example 8)

After the biaxially stretched film was again extended in the longitudinal direction, it was conveyed in an oven heated at a temperature of 180 ° C to carry out heat treatment, and a laminate film was obtained in the same manner as in Example 4. The obtained laminated film showed physical properties as shown in Table 1, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C). Further, high polarized light is displayed in the same manner as in the fourth embodiment. The reflection characteristics are very high performance as a polarizing reflection member. Further, in the obtained film, compared with Example 4, the heat shrinkage stress at 100 ° C and the absolute value of TMA can be suppressed to be low in the longitudinal direction of the film, and the laminated film can be processed on a specific condition. In addition, it is also stable for high precision and can be continuously produced, and can be used without any problem under the harsher conditions of the embodiment 4 in actual use.

(Example 9)

After the biaxially stretched film was again extended in the longitudinal direction, it was subjected to heat treatment in an oven heated at 220 ° C to carry out heat treatment, and a laminate film was obtained in the same manner as in Example 4. The obtained laminated film showed physical properties as shown in Table 2, and showed a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C). Further, in the same manner as in the fourth embodiment, high polarization reflection characteristics were exhibited, and the polarizing reflection member was extremely high in performance. Further, in the obtained film, compared with Example 4, the heat shrinkage stress at 100 ° C and the absolute value of TMA can be suppressed to be low in the longitudinal direction of the film, and the laminated film can be processed on a specific condition. In addition, it is also stable for high precision and can be continuously produced, and can be used without any problem under the harsher conditions of the embodiment 4 in actual use.

(Embodiment 10)

In addition to copolymerization of PEN (copolymerized PEN2) having a melting point of 240 ° C, a glass transition temperature of 118 ° C of 2,6-naphthalenedicarboxylic acid 50 mol%, spiroglycerol 5 mol%, and ethylene glycol 45 mol% copolymerization A laminate film was obtained in the same manner as in Example 4 except for the polyester. The obtained laminated film showed physical properties as shown in Table 2, and showed a high Young's modulus. The laminated film can be continuously produced when the product is processed under specific conditions, and can be used without any problem in actual use.

(Example 11)

A laminate film was obtained in the same manner as in Example 4 except that the copolymerized PEN2 was used as the thermoplastic resin B. The obtained laminated film showed physical properties as shown in Table 2, and showed a high Young's modulus as in Example 4. On the other hand, the difference in glass transition temperature between the crystalline polyester and the thermoplastic resin B was small, and the reflection performance was the same as in Example 1. The laminated film can be continuously produced with high precision and stability during processing of the product, and can be used without any problem in actual use.

(Embodiment 12)

In addition to polyethylene terephthalate (PET) having a melting point of 256 ° C and a glass transition temperature of 81 ° C as a crystalline polyester, a cyclopentane resin having an amorphous resin and a glass transition temperature of 78 ° C was used. In the same manner as in Example 4 except that methanol copolymerized PET (copolymerized PET) was used as the thermoplastic resin B, a laminated film was obtained. The obtained laminated film showed physical properties as shown in Table 2, and showed a high Young's modulus as compared with Comparative Examples 1 to 5. The laminated film can be continuously produced when the product is processed under specific conditions, and can be used without any problem in actual use. On the other hand, the crystalline polyester was derived from PET, and the reflection performance was lower than that of Example 4.

(Example 13)

In addition to the use of 2,6-naphthalene dicarboxylic acid 70 mol% and isophthalic acid 30 mol% as a dicarboxylic acid component having a glass transition temperature of 96 ° C, and ethylene glycol used as a diol component for copolymerization copolymerization PEN (copolymerized PEN3) as thermoplastic resin B, and examples 4 was carried out in the same manner to obtain a laminated film. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use.

(Example 14)

A laminate film was obtained in the same manner as in Example 13 except that the speed at which the film was extended in the longitudinal direction after the biaxial stretching was 400%/sec. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Example 15)

In addition to using a glass transition temperature of 90 ° C, 50 mol% of 2,6-naphthalene dicarboxylic acid and 50 mol% of isophthalic acid are used as a dicarboxylic acid component, and ethylene glycol is used as a diol component for copolymerization. PEN (copolymerized PEN4) was carried out in the same manner as in Example 4 except that thermoplastic resin B was used to obtain a laminated film. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Embodiment 16)

In addition to using a glass transition temperature of 98 ° C, 75 mol% of 2,6-naphthalene dicarboxylic acid and 25 mol% of isophthalic acid were used as the dicarboxylic acid. A layered film was obtained in the same manner as in Example 4 except that a copolymerized PEN (copolymerized PEN5) which was copolymerized as a diol component was used as the thermoplastic resin. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Example 17)

In addition to the use of a glass transition temperature of 103 ° C, 80 mol% of 2,6-naphthalene dicarboxylic acid and 20 mol% of isophthalic acid are used as a dicarboxylic acid component, and ethylene glycol is used as a diol component for copolymerization. PEN (copolymerized PEN6) was carried out in the same manner as in Example 4 except that thermoplastic resin B was used to obtain a laminated film. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Embodiment 18)

In addition to using a glass transition temperature of 103 ° C, 70 mol% of 2,6-naphthalene dicarboxylic acid and 30 mol% of 1,8-naphthalenedicarboxylic acid were used as a dicarboxylic acid component, and ethylene glycol was used as a diol component. A polymerized copolymerized PEN (copolymerized PEN7) was used as the thermoplastic resin B, and a laminate film was obtained in the same manner as in Example 4. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can also be continuously produced during processing of the product, and is not used in actual use. The problem can be used. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Embodiment 19)

In addition to using a glass transition temperature of 103 ° C, 70 mol% of 2,6-naphthalene dicarboxylic acid and 30 mol% of 2,3-naphthalene dicarboxylic acid were used as a dicarboxylic acid component, and ethylene glycol was used as a diol component. A polymerized copolymerized PEN (copolymerized PEN8) was used as the thermoplastic resin B, and a laminate film was obtained in the same manner as in Example 4. The obtained laminated film showed physical properties as shown in Table 3, and showed a high Young's modulus. The laminated film can be continuously produced during the processing of the product, and can be used without any problem in actual use. Further, the extinction ratio indicating the polarization characteristics was higher than that of Example 4, and the polarized light reflection performance was excellent.

(Comparative Example 1)

A film was obtained in the same manner as in Example 4 except that a single layer film of PEN was used as the cast film. The obtained film showed the physical properties as shown in Table 2, and showed a high Young's modulus as in Example 4. On the other hand, since it does not have a laminated structure, it does not show the specific reflection performance, and when it is compared with the film of Example 1, the film becomes brittle, and handling property falls. This film produces film breakage during processing of the article, and has poor continuous productivity.

(Comparative Example 2)

A laminate film was obtained in the same manner as in Example 1 except that a laminate having three slits was used. The obtained laminated film showed physical properties as shown in Table 2, and showed a high Young's modulus in the longitudinal direction of the film in the same manner as in Example 1. On the other hand, responding Since the number of layers was as small as three, and the reflection performance peculiar to the laminated structure was not exhibited, the film became brittle when compared with the film of Example 1, and the handleability was slightly lowered. This laminated film causes film breakage during processing of the product, and has poor continuous productivity.

(Comparative Example 3)

The cast film obtained in the same manner as in Example 4 was heated at a temperature of 120 ° C, and then stretched 4.5 times in the longitudinal direction of the film at a temperature set at 135 ° C, and then temporarily cooled.

The uniaxially stretched film obtained as described above is guided to a tenter, preheated by hot air at a temperature of 135 ° C, and then extended by 4.5 times in the film width direction at a temperature of 150 ° C, and continuously heated at 220. Heat treatment in an oven at °C. By arranging both ends of the obtained biaxially stretched film, a laminated film as a target was obtained as a film roll having a film width of 1500 mm and a length of 200 m.

The obtained laminated film showed physical properties as shown in Table 2, and the Young's modulus was lowered as compared with Example 4. This laminated film causes film breakage during processing of the product, and has poor continuous productivity.

(Comparative Example 4)

The cast film obtained in the same manner as in Example 4 was guided to a tenter, preheated by hot air at a temperature of 135 ° C, and then extended by 5.0 times in the film width direction at a temperature of 150 ° C, and the film was At the end of the refurbishment, a laminated film 200m as a target was obtained in the form of a roll having a film width of 2000 mm.

The obtained laminated film showed physical properties as shown in Table 2, and the Young's modulus decreased as compared with Example 4, which was the width of the film roll. Since the film has the alignment axis in the direction, the strength of the film roll in the winding axis direction is extremely weak. This laminated film causes film breakage during processing of the product, and has poor continuous productivity.

(Comparative Example 5)

The cast film obtained in the same manner as in Example 4 was heated at a temperature of 120 ° C, and then stretched 4.0 times in the longitudinal direction of the film at a temperature set at 135 ° C, and was refurbished. A film roll comprising a film having a film width of 500 mm and a length of 200 m was obtained as a target.

The obtained laminated film showed physical properties as shown in Table 2, and the Young's modulus was lowered as compared with Example 4. Further, as the orientation of the thermoplastic resin B generated during stretching, the reflection performance was significantly lowered as compared with the examples. This laminated film causes film breakage during processing of the product, and has poor continuous productivity.

Claims (14)

A laminated film comprising a layer A comprising a crystalline polyester and a laminated layer comprising a total of 11 or more layers of a B layer comprising a thermoplastic resin different from the crystalline polyester, wherein the laminated film is formed The Young's modulus in the direction of the alignment axis is 6 GPa or more. The laminated film according to claim 1, wherein in the polarized Raman spectrum having a beam diameter of 1 μm and a wavelength of 1390 cm ^-1 , the peak intensity I max of the direction in which the reflectance becomes maximum and the peak intensity I min of the direction orthogonal thereto are The ratio I max / I min is 5 or more. The laminated film according to claim 1, wherein the carboxylic acid component constituting the crystalline polyester contains 90 mol% or more of naphthalene dicarboxylic acid. The laminated film according to claim 1 or 2, wherein the absolute value of the linear expansion coefficient of the temperature of 40 ° C or more and 50 ° C or less in any of the direction of the alignment axis and the direction orthogonal to the direction of the alignment axis is 10 ppm / ° C the following. The laminated film of claim 1 or 2, wherein a reflectance at an incident angle of 10° is taken as R1 for a polarized component parallel to an incident surface including an alignment axis direction, and for a direction relative to the direction of the alignment axis The polarizing component perpendicular to the incident surface has a reflectance at an incident angle of 10° as R2, and the reflectance at a wavelength of 550 nm satisfies the following formulas (2) and (3); R2 (550) ≦ 40%. . . (2) . R1 (550) ≧ 70%. . . (3). The laminated film according to claim 1 or 2, wherein in the first heating curve of the differential calorimetry (hereinafter referred to as DSC), the laminated film has a melting peak, and the melting peak top temperature thereof is Tm, and is above Tm-110°C. The range below Tm-60 ° C has an exothermic peak. The laminated film according to claim 1 or 2, wherein a ratio of the direction of the alignment axis and the Young's modulus in the direction orthogonal to the same plane is 2 or more. The laminated film according to claim 1 or 2, wherein the heat shrinkage stress at a temperature of 100 ° C in the direction of the alignment axis is 1 MPa or less. The laminate film according to claim 1 or 2, wherein the absolute value of TMA at a temperature of 100 ° C in the direction of the alignment axis is 0.5% or less. The laminated film according to claim 1 or 2, wherein the melting peak derived from the thermoplastic resin B by differential scanning calorimetry (DSC) is 5 J/g or less. The laminate film of claim 1 or 2, wherein the layer A and the layer B satisfy the following conditions; A layer: an aromatic polyester containing a dicarboxylic acid component and a diol component as main constituent components, and 80 to 100 mol% of 100 mol% of the dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid, and the diol component 80 to 100 mol% of 100 mol% is ethylene glycol; B layer: an aromatic polyester containing a dicarboxylic acid component and a diol component as main constituent components, and 40 to 75 mol% of the dicarboxylic acid component in 100 mol% is 2,6-naphthalenedicarboxylic acid, 25 to 60 mol% Is a component selected from the group consisting of at least one of isophthalic acid, 1,8-naphthalenedicarboxylic acid, and 2,3-naphthalene dicarboxylic acid, wherein 80 to 100 mol% of the diol component is 100% by weight. Glycol. A film roll obtained by winding a laminated film of claim 1 or 2 along an alignment axis of the laminated film. The film roll of claim 12, wherein the laminated film has a width of 1000 mm or more. A method for producing a laminated film, characterized in that an A layer comprising a crystalline polyester and a B layer comprising a thermoplastic resin different from the crystalline polyester are laminated to form an unstretched film of 11 or more layers, The film has a longitudinal direction extending at a magnification of 2 to 5 times, and then extends 2 to 5 times in the film width direction, and again extends 1.3 to 4 times in the longitudinal direction of the film.