JP2017170886A - Laminate film and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film that can serve as a re-oriented film having high mechanical strength, dimensional stability and excellent optical characteristics, enabling processing with high yield and high accuracy in various kinds of processing steps and causing no failures when practically used.SOLUTION: The laminate film is composed of eleven layers or more in total produced by alternately laminating an A layer comprising a crystalline polyester and a B layer comprising a thermoplastic resin B different from the crystalline polyester and has a difference between a melting enthalpy (ΔHm) and a crystallization enthalpy (ΔHc) as observed in a differential scanning calorimetry (DSC) of 20 J/g or less.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film and a method for producing the same.

  Thermoplastic resin films, especially biaxially stretched polyester films, have excellent properties such as mechanical properties, electrical properties, dimensional stability, transparency and chemical resistance. It is widely used as a substrate film in the above applications.

On the other hand, a laminated film in which different resins are alternately laminated is used in the polyester film. Such a laminated film can be made into a film having a unique function that cannot be obtained by a single layer film. For example, a tear-resistant film with improved tear strength (see Patent Document 1) and infrared rays. Examples include an infrared reflection film that reflects light (see Patent Document 2), and a polarization reflection film that has polarization reflection characteristics (see Patent Document 3).
However, since such laminated films have a structure in which different resins are alternately laminated, the mechanical strength and dimensional stability tend to decrease due to the influence of the laminated thickness compared to a single-layer film. There is. When the mechanical strength and dimensional stability of a laminated film are reduced, for example, when it is combined with other various films and components into a functional film such as punching, cutting, coating, and laminating, the force applied to the film Deformation or breakage occurs, causing problems such as reduction in processing accuracy and yield during processing, and deterioration of the optical properties and quality of the obtained film, or dimensional changes when actually mounted on products etc. There is a problem that a problem associated with the problem occurs.

Japanese Patent No. 3960194 Japanese Patent No. 4310312 JP 2014-124845 A

In response to the above problems, the present inventors have found that a biaxially stretched film is stretched again to form a restretched film (International Application No. PCT / JP2016 / 052202). However, depending on the combination of resins used and the properties of the biaxially stretched film before stretching, it may have poor stretchability when stretched again, and a restretched film having physical properties satisfying desired mechanical strength, dimensional stability, and optical properties is obtained. I found out that sometimes I couldn't. In particular, there is a problem that optical characteristics typified by polarized light reflection characteristics disclosed in Patent Document 3 are not exhibited.

  Therefore, the object of the present invention is to solve the above-mentioned problems and to provide high mechanical strength, dimensional stability and excellent optical properties by stretching again, and to process with high yield and high accuracy in various processing steps. An object of the present invention is to provide a laminated film that can be made into a restretched film that does not cause problems during actual use.

  It is another object of the present invention to provide a polarizing reflector exhibiting excellent polarization reflection characteristics while having high mechanical strength and dimensional stability by stretching the laminated film again.

  The present invention is to solve the above-mentioned problem, and a total of 11 layers or more of A layers made of crystalline polyester and B layers made of thermoplastic resin B different from the crystalline polyester are alternately laminated. A difference between a melting enthalpy (ΔHm) and a crystallization enthalpy (ΔHc) observed in differential scanning calorimetry (DSC) (| ΔHc−ΔHm |) is 20 J / g or less. It is a laminated film.

  According to the present invention, when the laminated film of the present invention is stretched again to obtain a restretched film, it has high mechanical strength, dimensional stability, and excellent optical properties, and is punched and cut as various functional films. In addition, a laminated film that can be suitably used for processing and use such as coating and laminating, and has the effect of becoming a restretched film that can be used without causing problems during mounting can be obtained.

  The re-stretched film obtained by re-stretching the laminated film of the present invention is a film having high mechanical strength, dimensional stability, and excellent optical properties, so that it can be used as a process film and various optical films, particularly as a polarizing reflector. Appropriate film.

It is a schematic diagram showing polarized light perpendicular to the incident surface including the film longitudinal direction and polarized light parallel to the incident surface including the film longitudinal direction.

  Next, the laminated film of the present invention and the manufacturing method thereof will be described in detail.

  The laminated film of the present invention comprises a layer (A layer) made of crystalline polyester (hereinafter sometimes referred to as crystalline polyester A) and a thermoplastic resin different from the crystalline polyester (hereinafter referred to as thermoplastic resin B). A layered film in which a total of 11 or more layers (layer B) are alternately laminated.

  Here, specifically, the crystalline polyester A is a resin that is subjected to differential scanning calorimetry (hereinafter sometimes referred to as DSC) according to JIS K7122 (1999) and heated at a rate of temperature increase of 20 ° C./min. Is heated at a rate of temperature increase of 20 ° C./min from the temperature of 25 ° C. to 300 ° C. (1stRUN), held in that state for 5 minutes, then rapidly cooled to a temperature of 25 ° C. or lower, and again from 25 ° C. Polyester having a melting enthalpy (ΔHm) of 15 J / g or more determined from the peak area of the melting peak in a 2ndRUN differential scanning calorimetry chart obtained by raising the temperature to 300 ° C. at a temperature raising rate of ° C./min. Refers to that. More preferably, the melting enthalpy (ΔHm) is 20 J / g or more, and more preferably 25 J / g or more.

  Further, the thermoplastic resin B exhibits optical characteristics or thermal characteristics different from the crystalline polyester A used for the A layer. Specifically, in any of two orthogonal directions arbitrarily selected in the plane of the laminated film and a direction perpendicular to the plane, the crystalline polyester A has a refractive index different from 0.01 or more, or in DSC That which shows a melting point or glass transition temperature different from that of crystalline polyester A.

  In addition, the term “alternately laminated” here means that the A layer and the B layer are laminated in a regular arrangement in the thickness direction. For example, they are stacked in a regular arrangement represented by A (BA) n (n is a natural number). By alternately laminating resins with different optical properties in this way, it is possible to express interference reflection that can reflect the light of the designed wavelength from the relationship between the refractive index difference of each layer and the layer thickness. It becomes.

  In addition, by alternately laminating resins with different thermal properties, the orientation state of each layer can be controlled to a high degree when a biaxially stretched film or a biaxially stretched film that is a feature of the present invention is re-stretched. It becomes possible to control optical characteristics, mechanical characteristics, dimensional stability, and the like.

  As a preferable lamination form of the laminated film, A layer made of crystalline polyester A, B layer made of thermoplastic resin B different from crystalline polyester A, and thermoplastic resin different from crystalline polyester A and thermoplastic resin B A case of having a C layer made of C is also mentioned. In such a case, the layer C such as CA (BA) n, CA (BA) nC, and A (BA) nCA (BA) m may be stacked on the outermost layer or the intermediate layer.

  In addition, when the number of layers to be laminated is less than 11, for example, it is difficult to produce a biaxially stretched film due to the influence of physical properties such as film forming properties and mechanical properties when different thermoplastic resins are laminated. There is a possibility that a problem may occur when the product is combined with other components. Further, when the laminated film is stretched again, if the number of layers is less than 11 layers, the restretched film tends to become brittle, and the handling property may be lowered.

  On the other hand, in the case of a laminated film in which a total of 11 or more layers are alternately laminated as in the laminated film of the present invention, each thermoplastic resin is uniformly arranged as compared with a laminated film having a number of layers of less than 11 layers. In addition, it is possible to stabilize the film-forming property and mechanical properties, particularly the handling property of the re-stretched film by re-stretching by the interfacial tension at the lamination interface and the buffer effect of the B layer made of the thermoplastic resin B. . Also, as the number of layers increases, there is a tendency to suppress the growth of orientation in each layer.For example, it becomes easier to control mechanical properties and heat shrinkage properties such as improvement of tear resistance due to interfacial tension. In addition, it is possible to impart a specific optical characteristic that expresses the interference reflection function. The number of layers to be stacked is preferably 100 layers or more, and more preferably 200 layers or more. When 100 or more layers of films are laminated, it is possible to reflect a wide band of light with a high reflectivity, and when 200 or more layers are further laminated, for example, the entire visible light having a wavelength of 400 to 700 nm can be reflected. It becomes almost reflective. In addition, although there is no upper limit to the number of layers to be stacked, as the number of layers increases, it may cause an increase in manufacturing cost due to an increase in size and complexity of the manufacturing apparatus. It becomes.

  In the laminated film of the present invention, by stretching the laminated film again, it has high mechanical strength and dimensional stability, excellent optical properties, and can be processed with high yield and high accuracy in various processing steps. It is characterized in that it becomes a restretched film that does not cause any problems during actual use.

Therefore, in the laminated film of the present invention, the difference (| ΔHc−ΔHm |) between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) observed in the differential scanning calorimetry (DSC) is 20 J / g or less. is necessary. Here, the melting enthalpy is calculated from the peak area in the endothermic direction, and the crystallization enthalpy is calculated from the peak area in the exothermic direction, but when a plurality of peaks are confirmed, the total value of each peak is Melting enthalpy and crystallization enthalpy. The difference between melting enthalpy (ΔHm) and crystallization enthalpy (ΔHc) is a measure of the degree of crystallization of the laminated film. The larger the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc), the more the crystallization of the laminated film has progressed. Enthalpy is not observed. When the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) is larger than 20 J / g, the crystallization of the laminated film is progressing, so that even when trying to stretch the laminated film again, the high stretching tension or It becomes difficult to stretch due to low elongation at break, and it becomes difficult to obtain a restretched film having desired mechanical strength, dimensional stability, and optical properties. On the other hand, when the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) is 20 J / g or less, the crystallization of the laminated film has not progressed completely. It is possible to obtain high mechanical strength, dimensional stability, and excellent optical properties by sufficiently redrawing the stretched film.
Preferably, the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) is 3 J / g or more and 10 J / g or less. If the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) is less than 3 J / g, the laminated film has low crystallinity. May occur. If the difference between the melting enthalpy (ΔHm) and the crystallization enthalpy (ΔHc) is 3 J / g or more and 10 J / g or less, the draw ratio can be increased even when redrawing, resulting in a large adjustment of the draw ratio. As a result, mechanical strength, dimensional stability, and optical characteristics can be optimized, and it becomes easy to obtain a re-stretched film with higher performance and higher performance.

  In the laminated film of the present invention, the melting enthalpy (ΔHm) is preferably 15 J / g or more. When the melting enthalpy (ΔHm) is less than 15 J / g, the oriented crystallization of the re-stretched film is not sufficient, and in applications that require optical performance such as a polarizing reflector, it is made of a crystalline polyester. Reflective performance is manifested depending on the difference in the refractive index of each layer of the B layer made of the thermoplastic resin B different from the A layer and the crystalline polyester, so the orientation and crystallization of the crystalline polyester is not sufficient. In some cases, the desired optical performance is not exhibited. When the melting enthalpy (ΔHm) is 15 J / g or more, it is possible to easily introduce the refractive index difference between the A layer made of crystalline polyester and the B layer made of thermoplastic resin B different from the crystalline polyester. A restretched film having optical performance can be obtained.

  Moreover, in the laminated | multilayer film of this invention, it is also preferable that only one melting peak which is 5 J / g or more by a differential scanning calorimetry (DSC) is confirmed. The fact that only one melting peak of 5 J / g or more by differential scanning calorimetry (DSC) is confirmed means that the melting peak is derived from crystalline polyester, so that thermoplastic resin B is oriented and crystallized. Indicates that it is not. Therefore, it becomes easy to increase the refractive index difference between the layers A and B of the thermoplastic polyester B different from those of the crystalline polyester and obtain a redrawn film having high optical performance. It becomes possible.

  In the laminated film of the present invention, the MOR measured with a molecular orientation meter is preferably 1.5 or less. MOR represents the ratio between the maximum value and the minimum value of the dielectric constant in the in-plane direction of the film. In particular, in the case of a biaxially stretched film, the orientation / crystallization of the laminated film increases as the value of MOR increases. It becomes an index to show that When MOR is 1.5 or less, the crystallization of the laminated film has not progressed completely, so that it can be easily stretched when it is stretched again, and the stretched film is sufficiently restretched. As a result, high mechanical strength, dimensional stability, and excellent optical properties can be obtained.

  In the laminated film of the present invention, the elongation at break of a sample having a length of 150 mm × width of 10 mm at 160 ° C. in the film longitudinal direction of the laminated film or in a direction perpendicular to the longitudinal direction is preferably 200% or more. The film longitudinal direction here is defined as follows. In the case of a film wound in a roll shape, the roll winding direction is the film longitudinal direction. When the flow direction during film formation is known from the film, the flow direction is taken as the film longitudinal direction. For samples that cannot be distinguished by the two methods described above, the Young's modulus of the film is measured by changing the direction every 10 ° in the film plane, and the direction in which the Young's modulus is maximized is taken as the longitudinal direction of the film. When the film is stretched again, it is generally stretched in the film longitudinal direction or in a direction perpendicular to the longitudinal direction. Here, 160 ° C. is shown as an example of the temperature at the time of re-stretching, and if the elongation at break at the time of re-stretching is 150% or more, it can be easily stretched at the time of re-stretching. When the subsequent film is sufficiently restretched, high mechanical strength, dimensional stability, and excellent optical properties can be obtained. Preferably, the elongation at break at 160 ° C. is 250% or more, more preferably 300% or more. When re-stretching, the mechanical strength, dimensional stability, and optical properties can be optimized by increasing the stretch ratio or increasing the stretch ratio of the stretch ratio. Becomes easy.

  Further, the breaking elongation at 140 ° C. in the film longitudinal direction or the direction perpendicular to the longitudinal direction of the laminated film is preferably 150% or more, and more preferably the breaking elongation at 120 ° C. is 150% or more. If it is a laminated film that can be stretched even at lower temperatures, the choice of stretching method and stretching equipment will expand, and the physical properties of the re-stretched film can be adjusted by adjusting not only the stretching ratio but also the stretching temperature. In addition, it becomes easier to optimize the dimensional stability and optical characteristics. Note that the breaking elongation of a sample having a length of 150 mm × width of 10 mm does not match the breaking elongation in the actual film forming process due to the difference in sample width.

  In the laminated film of the present invention, the transmittance at an incident angle of 0 ° is perpendicular to the incident surface including the longitudinal direction of the laminated film with respect to the polarization component parallel to the incident surface including the film longitudinal direction of the laminated film. In the case where the transmittance at an incident angle of 0 ° is T2 with respect to a polarized light component, the minimum values of the transmittances T1 and T2 at wavelengths of 400 to 1400 nm are preferably 60% or more. As described above, the laminated film of the present invention is characterized in that it exhibits reflection characteristics due to the difference in refractive index between the A layer made of crystalline polyester and the B layer made of thermoplastic resin B different from the crystalline polyester. . That is, the reflectance (100-transmittance,%) is an index indicating the strength of orientation / crystallization of the A layer made of crystalline polyester, and the orientation / crystallization of the A layer increases as the reflectance increases. It shows that. Here, T1 is the transmittance at an incident angle of 0 ° for the polarization component parallel to the incident plane including the film longitudinal direction of the laminated film, and the incident light is for the polarization component perpendicular to the incident plane including the longitudinal direction of the laminated film. When the transmittance at an angle of 0 ° is T2, when the minimum values of the transmittances T1 and T2 at a wavelength of 400 to 1400 nm are both 60% or more, the orientation of the crystalline polyester is completely crystallization of the laminated film. Is not advanced, it can be easily stretched when it is stretched again, and the film after stretching is sufficiently restretched to obtain high mechanical strength, dimensional stability, and excellent optical properties. It becomes possible. Preferably, the minimum values of the transmittances T1 and T2 at wavelengths of 400 to 1400 nm are both 70% or more, and more preferably 80% or more. In this case, when stretching again, it becomes easy to increase the stretching ratio, and the mechanical strength, dimensional stability, and optical properties can be optimized by increasing the stretching ratio and adjusting the stretching ratio. It becomes easy to make a re-stretched film with higher function and higher performance.

Similarly, in the laminated film of the present invention, the maximum value of the degree of polarization P of the laminated film at a wavelength of 400 to 1400 nm determined from the following formula (1) is preferably 20% or less. The degree of polarization is not only an index similar to the minimum values of the transmittances T1 and T2 at wavelengths of 400 to 1400 nm, but also an index indicating the balance of orientation as in MOR measured by a molecular orientation meter. The maximum value of the degree of polarization P of the laminated film at a wavelength of 400 to 1400 nm being 20% or less indicates that the orientation and crystallization of the crystalline polyester is suppressed to a degree sufficient to be stretched again. The film can be easily stretched when it is stretched again, and the stretched film is sufficiently restretched to provide high mechanical strength, dimensional stability, and excellent optical properties. Can be obtained. More preferably, the maximum value of the degree of polarization P of the laminated film at a wavelength of 400 to 1400 nm is 10% or less, and when it is stretched again, it becomes easy to increase the draw ratio, and the draw ratio is increased and the draw ratio is increased. By increasing the adjustment width of the film, it is possible to optimize the mechanical strength, dimensional stability, and optical characteristics, and it becomes easy to obtain a re-stretched film with higher performance and higher performance.
P (λ) = (T2 (λ) −T1 (λ)) / (T2 (λ) + T1 (λ)) (1)
λ: Measurement wavelength (nm, 400-1400 nm)
In the laminated film of the present invention, the A layer made of crystalline polyester A is preferably the outermost layer. In this case, since the crystalline polyester A is the outermost layer, a biaxially stretched film can be produced in the same manner as a crystalline polyester film such as a polyethylene terephthalate film or a polyethylene naphthalate film. For example, when the thermoplastic resin B made of an amorphous resin is not the crystalline polyester but is the outermost layer, when obtaining a biaxially stretched film in the same manner as the crystalline polyester film, to production equipment such as rolls and clips There are cases where problems such as film formation failure due to adhesion and surface quality deterioration occur.

  As the crystalline polyester A used in the present invention, a polyester obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid or aliphatic dicarboxylic acid and a diol is preferably used.

  Here, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalene. Dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 6,6 '-(ethylenedioxy) di-2-naphthoic acid, 6, Examples include 6 '-(trimethylenedioxy) di-2-naphthoic acid and 6,6'-(butylenedioxy) di-2-naphthoic acid. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, and cyclohexanedicarboxylic acid and ester derivatives thereof. 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, a high refractive index is expressed after the maximum stretching, and from the viewpoint of increasing mechanical strength and dimensional stability represented by Young's modulus. Terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferably used. Since terephthalic acid and 2,6-naphthalenedicarboxylic acid contain aromatic rings with high symmetry, it is easy to achieve both high refractive index and excellent mechanical properties by orientation and crystallization. . In particular, when the carboxylic acid component constituting the crystalline polyester A contains 2,6-naphthalenedicarboxylic acid, the volume ratio of the aromatic ring is increased, so that the resin can be produced at low cost and can be melt-formed. It is possible to achieve a high refractive index and excellent mechanical properties.

  In addition to the terephthalic acid and 2,6-naphthalenedicarboxylic acid, the carboxylic acid component constituting the crystalline polyester A used in the laminated film of the present invention preferably contains isophthalic acid. By including isophthalic acid, the orientation after re-stretching can be easily increased while moderately suppressing the orientation and crystallinity of the laminated film as compared with the case of only terephthalic acid or 2,6-naphthalenedicarboxylic acid. It becomes possible.

  In the laminated film of the present invention, the crystalline polyester preferably contains 50 mol% or more of naphthalenedicarboxylic acid among the carboxylic acid components constituting the crystalline polyester. By including 50 mol% or more of naphthalenedicarboxylic acid, it is possible to easily cause orientational crystallization by further stretching the laminated film, and to easily increase the Young's modulus. Preferably, naphthalenedicarboxylic acid is contained in an amount of 50 mol% to 90 mol%. By adjusting the content of naphthalenedicarboxylic acid contained in the carboxylic acid component to 90 mol% or less, the orientation and crystallinity of the crystalline polyester can be appropriately suppressed, so that the stretching ratio can be increased or lower at a lower temperature. Since it becomes easy to extend | stretch, it can be made preferable as a laminated | multilayer film extended | stretched again.

  Examples of the diol component constituting the crystalline polyester include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2, Examples thereof include 2-bis (4-hydroxyethoxyphenyl) propane, isosorbate, and spiroglycol. Especially, it is a preferable aspect that ethylene glycol is a main component from a viewpoint that superposition | polymerization is easy.

  Here, the main component refers to 50 mol% or more of the diol component. These diol components may be used alone or in combination of two or more. It is also possible to partially copolymerize oxyacids such as hydroxybenzoic acid.

  In the laminated film of the present invention, it is also preferable that the diol component comprises at least two kinds and the content of the main diol component is 50 mol% or more and 90 mol% or less. In this case, since the orientation and crystallinity of the crystalline polyester can be moderately suppressed, it becomes easy to increase the draw ratio when stretching again and to stretch at a lower temperature, and thus is preferable as a laminated film to be stretched again. Can be.

  In the laminated film of the present invention, when the sum of all dicarboxylic acid components and all diol components constituting the crystalline polyester is 200 mol%, the sum of the main dicarboxylic acid components and dicarboxylic acids other than the diol components and the diol components is It is also preferable that it is less than 20 mol%. When the sum of the dicarboxylic acid other than the main dicarboxylic acid component and diol component and the diol component is less than 20 mol%, it is possible to increase the stretching ratio or to stretch at a lower temperature when stretching again with adequate crystallinity. Therefore, it can be made preferable as a laminated film that is stretched again, and the actually obtained laminated film can have high polarization reflection performance.

  More preferably, the layer A made of the crystalline polyester A of the present invention is made of a mixture of two or more kinds of crystalline polyesters and the thermoplastic resin B. Even in the case of a mixture of two or more types of crystalline polyester and thermoplastic resin B, the orientation and crystallinity of the crystalline polyester can be moderately suppressed, so that the stretching ratio is increased and the stretching is performed at a lower temperature when stretching again. Since it becomes easy, it can be made preferable as a laminated film stretched again. In addition, when controlling the orientation and crystallinity with the composition of the crystalline polyester, there are cases where problems occur in drying and extrusion of the resin when forming a film because the crystallinity of the resin itself is reduced. When two types of crystalline polyester and thermoplastic resin B are mixed, each resin is excellent in drying and extrudability, so that it becomes easy to stably form a film. As a further preferable effect of mixing two or more kinds of polyesters, the crystalline polyesters are dispersed with a small region called a domain without being completely mixed, so that crystallization proceeds in each domain, Although it has a low orientation and crystallinity necessary for stretching again, it exhibits the effect of suppressing film-forming troubles such as roll adhesion during stretching.

  Examples of the thermoplastic resin B used in the present invention include chain polyolefins such as polyethylene, polypropylene, and poly (4-methylpentene-1); ring-opening metathesis polymerization of norbornenes, addition polymerization, and addition copolymerization with other olefins. Polymers such as alicyclic polyolefins; polyamides such as nylon 6, nylon 11, nylon 12 and nylon 66, aramid, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal , Polyglycolic acid, polystyrene, styrene copolymer polymethyl methacrylate, polycarbonate; polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-na Polyesters such as tartrate, polylactic acid, polybutyl succinate; polyethersulfone, polyetheretherketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene resin, trifluoroethylene resin Trifluoroethylene chloride resin, tetrafluoroethylene-6 fluoropropylene copolymer, polyvinylidene fluoride, and the like can be used.

  Among these, from the viewpoint of strength, heat resistance, transparency, and versatility, polyester is preferably used from the viewpoints of adhesiveness and laminateability with the crystalline polyester A used for the A layer. These may be used as a copolymer or a mixture.

  In the laminated film of the present invention, when the thermoplastic resin B is a polyester, the polyester obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid component and / or an aliphatic dicarboxylic acid component and a diol component Is preferably used. Here, as the aromatic dicarboxylic acid component, the aliphatic dicarboxylic acid component, and the diol component, the components listed for the crystalline polyester A are preferably used.

  In the laminated film of the present invention, the thermoplastic resin B is preferably an aromatic polyester mainly comprising an aromatic dicarboxylic acid component and a diol component. Furthermore, in order to obtain a laminated film having an interference reflection function, the thermoplastic resin B is preferably an amorphous resin. Compared with crystalline resin, amorphous resin is less likely to be oriented when a biaxially stretched film is produced. Therefore, an increase in refractive index associated with orientation crystallization of B layer made of thermoplastic resin B can be suppressed, It is possible to easily generate a refractive index difference from the A layer made of the conductive polyester A.

  The non-crystalline resin here refers to heating the resin from 25 ° C. to 300 ° C. at a temperature rising rate of 20 ° C./min (1stRUN) according to JIS K7122 (1999). Then, after maintaining for 5 minutes in this state, it is then rapidly cooled to a temperature of 25 ° C. or less, and again heated from room temperature to a temperature of 300 ° C. at a rate of temperature increase of 20 ° C./min, and the obtained 2ndRUN In the differential scanning calorimetry chart, the heat of crystal melting ΔHm determined from the peak area of the melting peak is a resin having 5 J / g or less, more preferably a resin that does not show a peak corresponding to crystal melting.

  Further, in order to obtain a laminated film having an interference reflection function when the laminated film is re-stretched to obtain a re-stretched film, the thermoplastic resin B has a melting point that is 20 ° C. lower than the melting point of the crystalline polyester A. A crystalline resin is also preferably used. In this case, after re-stretching, further heat treatment is performed at a temperature between the melting point of the thermoplastic resin B and the melting point of the crystalline polyester A, so that it can be completely relaxed in the heat treatment step. The difference in refractive index with the A layer can be maximized. Preferably, the difference in melting point between the crystalline polyester A and the thermoplastic resin B is 40 ° C. or higher. In this case, since the temperature selection range in the heat treatment step is widened, the relaxation of the orientation of the thermoplastic resin B can be promoted and the orientation of the crystalline polyester can be more easily 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 is preferably 1.0 or less. When the absolute value of the difference in SP value is 1.0 or less, delamination between the A layer and the B layer is difficult to occur. More preferably, the crystalline polyester A and the thermoplastic resin B are made of a combination provided with the same basic skeleton.

  The basic skeleton here is a repeating unit constituting the resin. For example, polyethylene naphthalate having a carboxylic acid component consisting only of 2,6-naphthalenedicarboxylic acid as crystalline polyester A or a polyethylene naphthalate copolymer containing 50% or more of 2,6-naphthalenedicarboxylic acid as a main component When using a coalescence, it is preferable to use an amorphous polyethylene naphthalate copolymer or a crystalline polyethylene naphthalate copolymer having a melting point lower than that of the crystalline polyester A as the thermoplastic resin B.

  Further, in order to obtain a laminated film having an interference reflection function when the laminated film is drawn again to obtain a redrawn film, the glass transition temperature of the thermoplastic resin B is 10 ° C. or more than the glass transition temperature of the crystalline polyester A. Preferably it is low. In this case, since the orientation in the thermoplastic resin B does not proceed when the optimum stretching temperature is taken to stretch the crystalline polyester in each stretching step, the difference in refractive index from the A layer made of the crystalline polyester. Can be greatly increased. More preferably, the glass transition temperature of the thermoplastic resin B is 20 ° C. or more lower than the glass transition temperature of the crystalline polyester A.

  In a production method suitable for obtaining the laminated film of the present invention to be described later and a re-stretched film that has been stretched again, orientation crystallization of the thermoplastic resin B is likely to proceed, and the desired interference reflection function may not be obtained. By making the glass transition temperature of the thermoplastic resin B 20 ° C. or more lower than the glass transition temperature of the crystalline polyester A, oriented crystallization can be suppressed.

  In addition, various additives such as antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, charging agents are included in thermoplastic resins. An inhibitor, a nucleating agent, etc. can be added to such an extent that the characteristic is not deteriorated.

  Next, the preferable manufacturing method of the laminated | multilayer film of this invention is demonstrated about the following.

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

  First, crystalline polyester A and thermoplastic resin B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to a separate extruder. In the extruder, the resin melted by heating is made uniform in the extrusion amount of the resin by a gear pump or the like, and foreign matter, modified resin, or the like is removed through a filter or the like. These resins are fed into a multilayer laminating apparatus.

  As the multilayer laminating apparatus, a multi-manifold die, a feed block, a static mixer, or the like can be used. However, in order to efficiently obtain the configuration of the present invention, it is preferable to use a feed block having 11 or more fine slits. . By using such a feed block, the apparatus does not become extremely large, so that foreign matter due to thermal deterioration is small, and even when the number of stacks is extremely large, highly accurate stacking is possible. Also, the stacking accuracy in the width direction is significantly improved as compared with the prior art. Moreover, in this apparatus, since the thickness of each layer can be adjusted with the shape (length, width) of a slit, it becomes possible to achieve arbitrary layer thickness.

  And the lamination sheet discharged from die | dye is extruded on cooling bodies, such as a casting drum, and a casting film is obtained by cooling and solidifying. At this time, it is preferable that the discharged sheet is brought into close contact with the cooling body by an electrostatic force using an electrode such as a wire shape, a tape shape, a needle shape, or a knife shape, and is rapidly cooled and solidified. In addition, as a method of bringing the discharged sheet into close contact with the cooling body, a method of blowing air from a slit-like, spot-like or planar device and a method using a nip roll are also preferable modes.

  The casting film thus obtained is preferably biaxially stretched. Here, biaxial stretching refers to stretching the film in the longitudinal direction and the width direction. By biaxially stretching, it is possible to impart appropriate orientation and crystallinity to the crystalline polyester, and it becomes possible to obtain a laminated film suitable for stretching again.

  The obtained cast film is first stretched in the longitudinal direction. Stretching in the longitudinal direction is usually performed by the difference in the peripheral speed of the roll. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. Although it changes with kinds of resin as a draw ratio, it is preferred that it is 2 to 5 times. The purpose of the first stretching in the longitudinal direction is to provide the minimum orientation necessary for improving the uniform stretchability in the subsequent stretching in the film width direction. For this reason, when the stretching ratio is set to a ratio larger than 5 times, a film having a sufficient stretching ratio may not be obtained when the film width direction stretching described later and the laminated film are stretched again. Moreover, when the draw ratio is less than 2, the minimum orientation required for the next step cannot be imparted at the time of drawing, and thickness unevenness may occur in the longitudinal direction of the film, resulting in reduced quality. Further, the stretching temperature is preferably a temperature of glass transition temperature to glass transition temperature + 30 ° C. of crystalline polyester A constituting the laminated film.

  The uniaxially stretched film thus obtained is subjected to surface treatment such as corona treatment, flame treatment and plasma treatment as necessary, and then functions such as slipperiness, easy adhesion and antistatic property are inlined. It can be applied by coating.

  Subsequently, the uniaxially stretched film is stretched in the width direction. Stretching in the width direction is usually performed by using a tenter and transporting the film while holding both ends of the film with clips. Although it changes with kinds of resin as a magnification of extending, it is usually preferred that it is 2 to 5 times. The purpose of stretching in the width direction is to provide the minimum necessary orientation for imparting the high stretchability required when the laminated film is stretched again. For this reason, when the stretching ratio is set to a ratio larger than 5 times, a restretched film having a sufficient stretching ratio may not be obtained when the laminated film is stretched again. Further, when the draw ratio is less than 2, the thickness may be uneven in the film width direction at the time of drawing, and the quality may be lowered. Moreover, it is preferable that extending | stretching temperature is between the glass transition temperature of the crystalline polyester A which comprises a laminated | multilayer film-glass transition temperature +30 degreeC, or between the glass transition temperature-the crystallization temperature of crystalline polyester. The crystallization temperature of crystalline polyester here is the crystallization temperature observed in differential scanning calorimetry (DSC) of a uniaxially stretched film. When stretched at a temperature higher than 30 ° C. from the glass transition temperature, the minimum orientation required for the laminated film cannot be imparted for re-stretching. The quality of the stretched film may be reduced. In addition, when stretched at a temperature higher than the crystallization temperature of the crystallized polyester, the orientation and crystallization of the crystalline polyester proceeds at the time of stretching, and it may not be possible to impart the high stretchability required for re-stretching. There is. When the obtained laminated film is stretched again by stretching between the glass transition temperature of the crystalline polyester A constituting the laminated film to the glass transition temperature + 30 ° C., or between the glass transition temperature and the crystallization temperature of the crystalline polyester. The film can be easily stretched, and the stretched film is sufficiently restretched to obtain high mechanical strength, dimensional stability, and excellent optical properties.

  Usually, the biaxially stretched film thus obtained may be subjected to heat treatment at a temperature not lower than the stretching temperature and not higher than the melting point in the tenter in order to impart flatness and dimensional stability. In the laminated film, it is preferable not to apply heat above the stretching temperature after stretching. It is because crystallization may be accelerated | stimulated by applying the heat | fever more than extending | stretching temperature after extending | stretching.

  The laminated film of the present invention is a film suitable for stretching again. By performing stretching again by the following method, high mechanical strength, dimensional stability, and optical properties can be imparted.

  An example of a method of stretching again is shown below.

  As one example, the obtained biaxially stretched film is stretched in the longitudinal direction again. This stretching in the longitudinal direction is usually performed by the difference in the peripheral speed of the roll. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. Although the draw ratio varies depending on the type of resin, it is preferably 1.3 to 4 times. If it is the laminated | multilayer film of this invention, since it is excellent in a drawability also when extending | stretching again, it can also be extended | stretched 1.3 to 4 times easily. Moreover, it can be set as the film which shows a mechanical physical property, dimensional stability, and an optical characteristic as below-mentioned by extending | stretching 1.3 to 4 times. When the draw ratio is less than 1.3 times, mechanical properties, dimensional stability, and optical properties change due to redrawing are slightly changed, and a redrawn film having desired physical properties may not be obtained. On the other hand, when the draw ratio is larger than 4 times, the orientation of the redrawn film becomes strong, so that improvement of mechanical properties, dimensional stability, and optical properties can be achieved, but the redrawn film becomes brittle and depends on the application to be used. May result in an unsuitable film.

  Another example is when the obtained biaxially stretched film is stretched again in the width direction. The stretching in the width direction is usually performed by using a tenter and transporting the film while holding both ends of the film with clips. The preferred stretching ratio is the same as that when stretching in the longitudinal direction. In this way, as an effect of stretching in the width direction again, the orientation / crystal state of the laminated film is fixed by cooling the laminated film once compared with the case of increasing the draw ratio in the first width direction, and again By re-stretching, there is an effect that the re-stretched film can give a strong orientation.

  The restretched film thus obtained is preferably subjected to a heat treatment at a temperature not lower than the stretching temperature and not higher than the melting point in order to impart flatness and dimensional stability. By performing the heat treatment, the effect of improving the orientational crystallization and improving the mechanical properties is obtained, and the dimensional stability is improved as the orientation crystallization is promoted. After being heat-treated in this way, it is uniformly cooled and then cooled to room temperature and wound up. In addition, if necessary, a relaxation treatment or the like can be performed during the slow cooling after the heat treatment.

  The physical properties of the stretched film obtained are shown below.

  By re-stretching the laminated film of the present invention, the Young's modulus in the re-stretched direction can be improved. By setting the Young's modulus to 6 GPa, deformation can be suppressed even when force is applied to the laminated film during use as a processing film or a functional film such as punching, cutting, coating, and laminating. It becomes easy to suppress processing defects and performance changes during use. In the film stretched again by using the laminated film of the present invention, the ratio of Young's modulus in the direction perpendicular to the last stretched direction of the laminated film and the same plane can be set to 2 or more. In particular, it is easy to achieve a high Young's modulus as compared with the case of stretching at a high magnification.

  Further, by re-stretching the laminated film of the present invention, the absolute value of the linear expansion coefficient at a temperature of 40 ° C. to 50 ° C. in the re-stretched direction can be 10 ppm / ° C. or less. The coefficient of linear expansion is an index indicating the variability of the film size when the temperature is changed. By reducing the absolute value of the coefficient of thermal expansion, processing steps such as punching, cutting, coating, and laminating are performed. Even when the temperature of the laminated film changes during use or as a functional film, the deformation of the film can be suppressed, and it becomes easy to suppress the processing defects accompanying the deformation of the film and the performance change during use. .

  By redrawing the laminated film of the present invention, it becomes easy to obtain a polarizing reflector.

  In the laminated film of the present invention, the magnification at which the film breaks when the laminated film is stretched in the longitudinal direction is X times, and the magnification at which the film breaks when the laminated film is stretched in the direction perpendicular to the longitudinal direction is X 'times. A laminated film obtained by stretching the laminated film in the longitudinal direction by (X-0.2) times, or a laminated film obtained by stretching the laminated film in a direction perpendicular to the longitudinal direction by (X'-0.2) times. The reflectance at an incident angle of 10 ° for a polarization component parallel to the incident surface including the stretching direction of the film is R3, and the reflectance at an incident angle of 10 ° for a polarization component perpendicular to the incident surface including the stretching is R4. In this case, it is preferable that the reflectance at a wavelength of 550 nm satisfies the following formulas (2) and (3). By satisfying the following formulas (2) and (3), it becomes possible to impart a polarization reflection characteristic of reflecting either polarized light and transmitting the other polarized light. In order to obtain a film satisfying the following formula (2), the refractive index difference between the A layer and the B layer in the last stretched direction of the laminated film is 0.08 or more, more preferably 0.1 or more, Preferably, it can be adjusted by selection of a combination of resins of 0.15 or more and film forming conditions. In order to obtain a film satisfying the following formula (3), the difference in refractive index between the A layer and the B layer in the direction orthogonal to the last stretched direction of the laminated film is 0.02 or less, more preferably 0. It can be adjusted by a combination of resins of 01 or less, more preferably 0.005 or less. Examples of the optimum combination are as described above.

R3 (550) ≧ 70% Formula (2)
R4 (550) ≦ 40% Formula (3).

(Characteristic measurement method and effect evaluation method)
The characteristic measurement method and effect evaluation method in the present invention 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 using a transmission electron microscope (TEM). That is, using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), a cross-sectional photograph of the film was taken under the condition of an acceleration voltage of 75 kV, and the number of layers was confirmed.

(2) Film crystallization enthalpy (ΔHc), melting enthalpy (ΔHm), number of melting peaks of 5 J / g or more:
Sampling was performed from the laminated film to be measured, and the DSC curve of the measurement sample was measured according to JIS-K-7122 (1987) using differential calorimetry (DSC). In the test, the temperature was raised from 25 ° C. to 290 ° C. at 20 ° C./min, and the number of crystallization enthalpies and melting enthalpies at that time and the number of melting peaks of 5 J / g or more were measured. The apparatus etc. which were used are as follows.
・ Device: “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd.
・ Data analysis "Disk Session SSC / 5200"
・ Sample mass: 5mg
(3) MOR
The sample size was 10 cm × 10 cm, and a sample was cut out at the center in the film width direction. MOR was determined using a molecular orientation meter MOA-2001 manufactured by KS Systems (currently Oji Scientific Instruments).

(4) Measurement of reflectance and transmittance for incident light having a polarization component:
The laminated film was cut out at 5 cm × 5 cm from the center of the alignment axis direction on the line segment having the maximum length in the alignment axis direction (one of the definitions of the longitudinal direction) determined by Young's modulus measurement. A basic configuration using an integrating sphere attached to a spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd., and measurement was performed with reference to an auxiliary white plate of aluminum oxide attached to the apparatus. The sample was placed behind the integrating sphere with the orientation direction of the laminated film being the vertical direction. In addition, a polarizer made by the attached Grantera Co., Ltd. was installed, and linearly polarized light whose polarization component was polarized at 0 and 90 ° was incident, and the reflectance and transmittance at a wavelength of 400 to 1400 nm were measured. The transmittance at an incident angle of 0 ° for a polarization component parallel to the incident surface including the film longitudinal direction is T1, and the transmission at an incident angle of 0 ° for the polarization component perpendicular to the incident surface including the longitudinal direction of the laminated film The rate was T2, and the minimum values of the transmittances T1 and T2 at wavelengths of 400 to 1400 nm were determined.
Similarly, the restretched laminated film was cut out at 5 cm × 5 cm from the center of the direction orthogonal to the restretched direction. The cut sample was placed behind the integrating sphere with the direction of re-stretching of the laminated film being the vertical direction.
The film longitudinal direction here is defined as follows. In the case of a film wound in a roll shape, the roll winding direction is the film longitudinal direction. When the flow direction during film formation is known from the film, the flow direction is taken as the film longitudinal direction. In a sample that cannot be distinguished by the above two methods, the Young's modulus of the film is measured by changing the direction every 10 ° in the film plane, and the direction in which the Young's modulus is maximized is defined as the film longitudinal direction.

  The measurement conditions are as follows. The slit was set to 2 nm (visible) / automatic control (infrared), the gain was set to 2, the scanning speed was measured at 600 nm / min, and the reflectance at an azimuth angle of 0 to 180 degrees was obtained. When measuring the reflection of the sample, it was painted black with Magic Ink (registered trademark) in order to eliminate interference caused by reflection from the back surface.

Further, the transmittance was measured in the same manner without blacking out the sample cut out in the same manner, and the degree of polarization P was determined in the wavelength range of 400 to 1400 nm by the following equation (1) from the obtained transmittance data. .
P (λ) = (T2 (λ) −T1 (λ)) / (T2 (λ) + T1 (λ)) (1)
(5) Young's modulus of the redrawn film:
The re-stretched laminated film was cut into a strip shape having a length of 150 mm and a width of 10 mm to prepare a sample. Using a tensile tester (Orientec Tensilon UCT-100), an initial tensile chuck distance was set to 50 mm, and a tensile speed was set to 300 mm / min. The measurement was carried out in an atmosphere at room temperature of 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 five times for each sample, and the average value was evaluated.
(6) Breaking elongation of laminated film:
The laminated film was cut into a rectangular shape having a length of 150 mm and a width of 10 mm in the direction of the orientation axis determined by Young's modulus measurement and the direction orthogonal to the orientation axis direction, and used as a sample. A tensile test was performed using a thermostatic chamber adjusted to 160 ° C. and a tensile tester (Tensilon UCT-100 manufactured by Orientec Co., Ltd.) with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. The point at which the maximum load was obtained from the obtained load-strain curve was defined as the breaking elongation. The measurement was performed five times for each sample, and the average value was evaluated.

(7) Fracture ratio when re-stretching in the longitudinal direction of the laminated film After the laminated film was slit to a width of 400 mm, it was heated to 125 ° C. with six rolls having a diameter of 200 mm. Then, after heating with a radiation heater, it is nipped from the top and bottom with two rolls (stretching rolls) with a diameter of 120 mm heated to 160 ° C., and cooled to 25 ° C. installed so that the length of the stretching section becomes 124 mm. The film was passed through a roll (cooling roll) having a diameter of 120 mm and wound up. Thereafter, the magnification between the stretching roll and the cooling roll is increased by 1.1 to 0.1 times until the film breaks, and the magnification X at which the film breaks when stretched in the longitudinal direction with the film breaking ratio. did.

(8) Breaking magnification when re-stretching in the direction orthogonal to the longitudinal direction of the laminated film After slitting the laminated film to a width of 400 mm, the both ends of the film are held by the clips of the tenter and directed from the inlet to the outlet. It was widened and stretched so that the rail width was 1.1 times and wound up at the tenter outlet. Thereafter, the rail width is increased by 0.1 times, and the magnification X at which the film breaks when the film is stretched in the direction perpendicular to the longitudinal direction with the magnification broken in the longitudinal direction or the direction perpendicular to the longitudinal direction. 'And.

(9) Linear expansion coefficient:
The re-stretched laminated film was cut into a strip shape having a length of 25 mm and a width of 4 mm in the direction of the orientation axis, and used as a sample. Using a TMA testing machine (TMA / SS6000 manufactured by Seiko Instruments Inc.), the initial tensile chuck distance is 15 mm, and the tensile temperature is kept constant at 29.4 mN. The TMA measurement was performed for the orientation axis direction of the laminated film. From the obtained TMA-temperature curve, the linear expansion coefficient at a temperature of 40 ° C. to 50 ° C. was determined. The linear expansion coefficient was determined from the difference between the values to be measured at ± 5 ° C. for both TMA and temperature.

(10) Workability:
A roll-shaped film was introduced into a punching machine, the length was 500 mm, and punching was performed using a rectangular mold having a width of 95% with respect to the film width. The punching interval in the longitudinal direction was 40 mm. The following A, B and C evaluations were made. A and B were accepted.
A: The film could be continuously conveyed and processed without breaking.
B: Although the film was partially broken, continuous conveyance in the longitudinal direction was possible and the film could be processed continuously.
C: The film was completely broken and continuous processing in the longitudinal direction could not be performed.

(11) Mounting test:
A laminated film as a sample was cut out from the position of the central part in the film width direction at a size of 1450 mm in the longitudinal direction × 820 mm in the width direction. Next, on the 32-inch LCD TV LHD32K15JP backlight manufactured by Hisense Japan Co., Ltd., a 50% diffuser plate, a microlens sheet, a polarizing reflector, and a polarizing plate were installed in this order, and at 60 ° C. heat resistance test and 60 ° C. 90% RH. The flatness of the polarizing reflector after the heat and humidity resistance test of 12 hours was evaluated visually.

The flatness was evaluated by the following A, B and C. A was accepted.
A: There is no appearance problem in the heat resistance test and moist heat resistance test B: There is an appearance problem in any of the tests.

(12) Naphthalene dicarboxylic acid content:
The layer A of the laminated film made of crystalline polyester was dissolved in deuterated hexafluoroisopropanol (HFIP) or a mixed solvent of HFIP and deuterated chloroform, and the composition was analyzed using ¹ H-NMR and ¹³ C-NMR. .

Example 1
As 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. The thermoplastic resin B is an amorphous resin having no melting point, has a glass transition temperature of 103 ° C., 2,6-naphthalenedicarboxylic acid 50 mol% and terephthalic acid 50 mol% as a dicarboxylic acid component, and a diol component. Copolymerized PEN copolymerized with 100 mol% of ethylene glycol (copolymerized PEN1) was used.

  The prepared crystalline polyester A and thermoplastic resin B were put into two single-screw extruders, melted at a temperature of 290 ° C., and kneaded. Next, the crystalline polyester A and the thermoplastic resin B are passed through 5 sheets of FSS type leaf disk filters, and then combined with a laminating apparatus having 11 slits while being measured with a gear pump. A laminate in which 11 layers were alternately laminated was obtained. The method of forming a laminate was performed according to the method described in Japanese Unexamined Patent Publication No. 2007-307893 [0053] to [0056].

  Here, the length and interval of the slits were all constant. The obtained laminate had 6 layers of crystalline polyester A and 5 layers of thermoplastic resin B, and had a laminated structure in which the layers were alternately laminated in the thickness direction. Further, the value obtained by dividing the length in the film width direction of the base lip, which is the widening ratio inside the base, by the length in the film width direction at the inlet of the base was set to 2.5.

  The obtained cast film was heated with a roll group set at a temperature of 120 ° C., stretched 3.3 times with a roll set at a temperature of 135 ° C. in the longitudinal direction of the film, and then cooled once. The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 115 ° C., and then stretched 3.5 times in the film width direction at a temperature of 135 ° C. to obtain a biaxially stretched film as a film roll. It was.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between melting enthalpy and crystallization enthalpy was small, and both MOR and transmittance were low.

  The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 1.6 times. . Therefore, the film was stretched 1.4 times in the longitudinal direction of the film to obtain a restretched film.

  The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. On the other hand, although it exhibited interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, it did not have sufficient performance for use as a polarizing reflector.

(Example 2)
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 101 slits.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between melting enthalpy and crystallization enthalpy was small, and both MOR and transmittance were low.

  The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 1.9 times. . Therefore, the film was stretched 1.7 times in the longitudinal direction of the film to obtain a restretched film.

  The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Further, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B. Even when compared with Example 1, it showed high polarization reflection characteristics.

(Example 3)
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 201 slits.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between melting enthalpy and crystallization enthalpy was small, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 2.1 times. . Therefore, the film was stretched 1.9 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and exhibits high polarization reflection characteristics as compared with Example 2, and can be used as a polarization reflection member. It was possible level.

Example 4
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 401 slits.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between melting enthalpy and crystallization enthalpy was small, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 2.4 times. . Therefore, the film was stretched 2.2 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Further, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and exhibits high polarization reflection characteristics even compared with Example 3, and is extremely high as a polarization reflection member. It was performance.

(Example 5)
Copolymerization of crystalline polyester with a glass transition temperature of 119 ° C., 2,6-naphthalenedicarboxylic acid 100 mol% as a dicarboxylic acid component, and ethylene glycol 90 mol% and neopentyl glycol 10 mol% as a diol component A laminated film was obtained in the same manner as in Example 4 except that PEN (copolymerized PEN2) was used.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between the enthalpy of fusion and the crystallization enthalpy was smaller than that of Example 4, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film was broken. The draw ratio (breaking elongation X at 160 ° C.) was 2.8 times. . Therefore, the film was stretched 2.6 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. In addition, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and even higher polarization reflection characteristics than those of Example 4, and is very useful as a polarization reflection member. High performance.

(Example 6)
Copolymerized PEN copolymerized with crystalline polyester having a glass transition temperature of 117 ° C., using 90 mol% of 2,6-naphthalenedicarboxylic acid and 10 mol% of terephthalic acid as a dicarboxylic acid component, and 100 mol% of ethylene glycol as a diol component. A laminated film was obtained in the same manner as in Example 4 except that (copolymerized PEN3) was used.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between the enthalpy of fusion and the crystallization enthalpy was smaller than that of Example 4, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film was broken, and the draw ratio (breaking elongation X at 160 ° C.) was 3.0 times. . Therefore, the film was stretched 2.8 times in the film longitudinal direction to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. In addition, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and even higher polarization reflection characteristics than those of Example 4, and is very useful as a polarization reflection member. High performance.

(Example 7)
Copolymerized PEN copolymerized with crystalline polyester having a glass transition temperature of 117 ° C., using 70 mol% of 2,6-naphthalenedicarboxylic acid and 30 mol% of terephthalic acid as a dicarboxylic acid component, and 100 mol% of ethylene glycol as a diol component. A laminated film was obtained in the same manner as in Example 4 except that (copolymerized PEN4) was used.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between the enthalpy of fusion and the crystallization enthalpy was smaller than that of Example 4, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 4.0 times. . Therefore, the film was stretched 3.8 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Moreover, although it showed the interference reflection characteristic derived from the difference in the refractive index of crystalline polyester A and thermoplastic resin B, when compared with Example 4, it reflects the characteristic of crystalline polyester and has a slightly lower polarization reflection characteristic. Indicated.

(Example 8)
The cast film obtained in the same manner as in Example 5 was made into a biaxially stretched film by the following production method.
The cast film was heated by a group of rolls set to a temperature of 120 ° C., stretched 2.8 times by a roll set to a temperature of 135 ° C. in the longitudinal direction of the film, and then cooled once. The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 115 ° C., and then stretched 3.5 times in the film width direction at a temperature of 135 ° C. to obtain a biaxially stretched film as a film roll. It was.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between the enthalpy of fusion and the crystallization enthalpy was even smaller than in Example 5, and both MOR and transmittance were low.

The obtained laminated film was further heated with a roll group set at a temperature of 160 ° C. and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 4.2 times. . Therefore, the film was stretched 4.0 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Moreover, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, shows the polarization reflection characteristics at the same level as in Example 5, and has very high performance as a polarization reflection member. there were. On the other hand, some unevenness in performance was seen in the film longitudinal direction.

Example 9
The cast film obtained in the same manner as in Example 5 was made into a biaxially stretched film by the following production method.
The cast film was heated by a group of rolls set at a temperature of 10 ° C., stretched 4.2 times with a roll set at a temperature of 135 ° C. in the longitudinal direction of the film, and then cooled once. The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 115 ° C., and then stretched 3.5 times in the film width direction at a temperature of 135 ° C. to obtain a biaxially stretched film as a film roll. It was.

The physical properties of the obtained laminated film are shown in Table 1, and the difference between melting enthalpy and crystallization enthalpy and MOR and transmittance are also larger than those in Example 5,
The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C. and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 2.0 times. . Therefore, the film was stretched 1.8 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Moreover, although the interference reflection characteristic derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B is shown, the polarization reflection characteristic was slightly lowered as compared with Example 5.

(Example 10)
Using the laminated film obtained in Example 5, the film was redrawn as follows to obtain a redrawn film.

The resulting laminated film was further guided to a tenter, preheated with hot air at a temperature of 115 ° C., and then stretched at a temperature of 160 ° C. until the film was broken. The draw ratio (breaking elongation X at 160 ° C.) was 2. The stretching was 0 times. Therefore, the film was stretched 1.8 times in the film width direction to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film width direction corresponding to the redraw direction. The numerical value was slightly lower than that, and the curl was slightly observed in the wet heat test even when processed into a product or during actual use. Moreover, although the interference reflection characteristic derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B was exhibited, the polarization reflection characteristic was lower than that in Example 5.

(Example 11)
A laminated film was obtained in the same manner as in Example 4 except that 10% by weight of copolymerized PEN1 and 90% by weight of copolymerized PEN2 were mixed and used as the crystalline polyester.

  The physical properties of the obtained laminated film are shown in Table 1. The difference between the melting enthalpy and the crystallization enthalpy was small as in Example 5, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 3.4 times. . Therefore, the film was stretched 3.2 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 1, and show a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. Moreover, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B. Compared with Example 5, the effect obtained by mixing two types of resins and higher polarization It showed reflection characteristics and was very high performance as a polarized light reflecting member.

Example 12
As the crystalline polyester, the glass transition temperature is 112 ° C., 95 mol% of 2,6-naphthalenedicarboxylic acid and 5 mol% of isophthalic acid are used as the dicarboxylic acid component, and 90 mol% of ethylene glycol and 10 mol% of neopentyl glycol are used as the diol component. Copolymerized copolymer PEN (copolymerized PEN5) is an amorphous resin having no melting point as the thermoplastic resin B, has a glass transition temperature of 98 ° C., and 50 mol% of 2,6-naphthalenedicarboxylic acid as a dicarboxylic acid component. Lamination was carried out in the same manner as in Example 4 except that 50 mol% of terephthalic acid was used, and copolymerized PEN (copolymerized PEN6) copolymerized using 90 mol% of ethylene glycol and 10 mol% of neopentyl glycol as the diol component was used. A film was obtained.

  The physical properties of the obtained laminated film are shown in Table 2. The difference between the melting enthalpy and the crystallization enthalpy was even smaller than in Example 5, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 3.2 times. . Therefore, the film was stretched 3.0 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 2, which shows a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. In addition, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and even higher polarization reflection characteristics than those of Example 4, and is very useful as a polarization reflection member. High performance.

(Example 13)
Thermoplastic resin B is an amorphous resin having no melting point, has a glass transition temperature of 92 ° C., uses 35 mol% of 2,6-naphthalenedicarboxylic acid and 65 mol% of terephthalic acid as a dicarboxylic acid component, and ethylene glycol as a diol component A laminated film was obtained in the same manner as in Example 12 except that 90 mol% and copolymerized PEN (copolymerized PEN 6) copolymerized using neopentyl glycol 10 mol% were used.

  The physical properties of the obtained laminated film are shown in Table 2. The difference between the melting enthalpy and the crystallization enthalpy was even smaller than in Example 5, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 3.4 times. . Therefore, the film was stretched 3.2 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 2, which shows a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the film longitudinal direction corresponding to the redraw direction. Even in actual use, it could be used satisfactorily. In addition, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and even higher polarization reflection characteristics than those of Example 4, and is very useful as a polarization reflection member. High performance.

(Example 14)
As a crystalline polyester, a glass transition temperature is 110 ° C., 90 mol% of 2,6-naphthalenedicarboxylic acid and 10 mol% of isophthalic acid are used as a dicarboxylic acid component, and 90 mol% of ethylene glycol and 10 mol% of neopentyl glycol are used as diol components. A laminated film was obtained in the same manner as in Example 13 except that copolymerized copolymer PEN (copolymerized PEN8) was used.

  The physical properties of the obtained laminated film are shown in Table 2. The difference between the melting enthalpy and the crystallization enthalpy was even smaller than in Example 5, and both MOR and transmittance were low.

The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film was broken, and the draw ratio (breaking elongation X at 160 ° C.) was 3.0 times. . Therefore, the film was stretched 2.8 times in the film longitudinal direction to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 2, and show a high Young's modulus and a low coefficient of linear expansion (40 to 50 ° C.) in the longitudinal direction of the film corresponding to the redraw direction. The rate was low, and the handleability during processing was slightly inferior. Moreover, although the interference reflection characteristic derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B was exhibited, the polarization reflection characteristic was slightly lowered as compared with Example 4.

(Comparative Example 1)
A film (corresponding to the laminated film of Example 1) was obtained in the same manner as in Example 1 except that a single-layer film of PEN was used as the cast film. The physical properties of the obtained film are shown in Table 2. The difference between the melting enthalpy and the crystallization enthalpy was large, and the MOR was higher than that in Example 1.

  The obtained film was further heated with a group of rolls set at a temperature of 160 ° C. and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 1.5 times. Therefore, the film was stretched 1.3 times in the longitudinal direction of the film to obtain a restretched film.

  The physical properties of the obtained redrawn film are shown in Table 2, but those having a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the longitudinal direction of the film corresponding to the redraw direction and not having a laminated structure. In addition, the specific reflection performance was not shown, and the film was more fragile than the film of Example 1, so that the handling property was lowered. This film was inferior in continuous productivity due to film breakage during processing into a product.

(Comparative Example 2)
A film (corresponding to the laminated film of Example 1) was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having three slits. The physical properties of the obtained film are shown in Table 2. The difference between the melting enthalpy and the crystallization enthalpy was large, and the MOR was higher than that in Example 1.

  The obtained film was further heated with a group of rolls set at a temperature of 160 ° C. and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 1.6 times. Therefore, the film was stretched 1.4 times in the longitudinal direction of the film to obtain a restretched film.

  The physical properties of the obtained redrawn film are shown in Table 2, but those having a high Young's modulus and a low linear expansion coefficient (40 to 50 ° C.) in the longitudinal direction of the film corresponding to the redraw direction and not having a laminated structure. In addition, the specific reflection performance was not shown, and the film was more fragile than the film of Example 1, so that the handling property was lowered. This film was inferior in continuous productivity due to film breakage during processing into a product.

(Comparative Example 3)
After heating the cast film obtained in the same manner as in Example 5 with a roll group set at a temperature of 120 ° C., the film was stretched 4.5 times with a roll set at a temperature of 135 ° C. in the longitudinal direction of the film, Then it was once cooled.

  The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 135 ° C, and then stretched 4.5 times in the film width direction at a temperature of 150 ° C to obtain a biaxially stretched film as a film roll It was.

The physical properties of the obtained laminated film are shown in Table 2, and the difference between melting enthalpy and crystallization enthalpy and MOR and transmittance are also larger than those in Example 5,
The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C. and then stretched until the film broke, and the draw ratio (breaking elongation X at 160 ° C.) was 1.5 times. . Therefore, the film was stretched 1.3 times in the longitudinal direction of the film to obtain a restretched film.
The physical properties of the obtained redrawn film are shown in Table 2, but the Young's modulus in the film longitudinal direction corresponding to the redraw direction and the linear expansion coefficient (40 to 50 ° C.) are both lower than those in Example 5, Film breakage occurred during processing into products, and continuous productivity was poor.

(Comparative Example 4)
After heating the cast film obtained in the same manner as in Example 5 with a roll group set at a temperature of 120 ° C., the film was stretched 4.5 times with a roll set at a temperature of 135 ° C. in the longitudinal direction of the film, Then it was once cooled.

  The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 135 ° C, stretched 4.5 times in the film width direction at a temperature of 150 ° C, and further continuously heated to 220 ° C. Heat treatment was carried out by transporting through the oven. By trimming both ends of the obtained biaxially stretched film, the target laminated film was obtained as a film roll.

The physical properties of the obtained laminated film are shown in Table 2, and the difference between melting enthalpy and crystallization enthalpy and MOR and transmittance are also larger than those in Example 5,
The obtained laminated film was further heated with a group of rolls set at a temperature of 160 ° C., and then stretched until the film broke, but it was broken immediately without stretching at all, and was not suitable for the production of a restretched film. there were.

1. 1. Film longitudinal direction 2. Polarized light perpendicular to the incident plane including the longitudinal direction of the film Polarized light parallel to the incident plane including the film longitudinal direction

Claims (9)

  A laminated film formed by alternately laminating a total of 11 or more layers of layer A composed of crystalline polyester and layer B composed of thermoplastic resin B different from the crystalline polyester, and is observed in differential scanning calorimetry (DSC) A laminated film having a difference (| ΔHc−ΔHm |) of 20 J / g or less between a melting enthalpy (ΔHm) and a crystallization enthalpy (ΔHc). The laminated film according to claim 1, wherein the elongation at break of a sample having a length of 150 mm and a width of 10 mm at 160 ° C in a film longitudinal direction or a direction orthogonal to the longitudinal direction of the laminated film is 200% or more.   The laminated film according to claim 1 or 2, wherein the MOR measured by a molecular orientation meter is 1.5 or less.   The transmittance at an incident angle of 0 ° for the polarization component parallel to the incident plane including the film longitudinal direction of the laminated film is T1, and the incident angle of 0 ° for the polarized component perpendicular to the incident plane including the longitudinal direction of the laminated film. 4. The laminate according to claim 1, wherein the minimum value of the transmittances T <b> 1 and T <b> 2 at wavelengths of 400 to 1400 nm is 60% or more, where T <b> 2 is T <b> 2. the film. The laminated film P according to any one of claims 1 to 4, wherein the maximum value of the degree of polarization P of the laminated film at a wavelength of 400 to 1400 nm determined from the following formula (1) is 20% or less. (Λ) = (T2 (λ) −T1 (λ)) / (T2 (λ) + T1 (λ)) (1)
λ: Measurement wavelength (nm, 400-1400 nm)   The laminated film according to any one of claims 1 to 5, wherein among the carboxylic acid components constituting the crystalline polyester, naphthalenedicarboxylic acid is contained in an amount of 50 mol% or more.   The laminated film according to any one of claims 1 to 6, wherein only one melting peak of 5 J / g or more is confirmed by differential scanning calorimetry (DSC). When the laminated film is stretched in the longitudinal direction, the magnification at which the film breaks is X times, and when the laminated film is stretched in the direction perpendicular to the longitudinal direction, the magnification at which the film is broken is X ′ times, the laminated film The incident surface including the stretching direction of the laminated film obtained by stretching (X-0.2) times in the longitudinal direction, or the laminated film obtained by stretching the laminated film in the direction orthogonal to the longitudinal direction (X'-0.2) times Reflectance at a wavelength of 550 nm when the reflectance at an incident angle of 10 ° is R3 for a polarized light component parallel to the angle R4 and the reflectance at an incident angle of 10 ° is R4 for a polarized light component perpendicular to the incident surface including stretching. The rate satisfies the following formulas (2) and (3): The laminated film according to claim 1.
R3 (550) ≧ 70% Formula (2)
R4 (550) ≦ 40% Formula (3). The manufacturing method of the polarizing reflector which manufactures the polarizing reflector which extends | stretches the laminated | multilayer film in any one of Claims 1-8 1.3-4 times, and satisfies following formula (2) and Formula (3).
R3 (550) ≧ 70% Formula (2)
R4 (550) ≦ 40% Formula (3).

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