JP2019139228A - Film and manufacturing method for the same - Google Patents

Abstract

To provide a film that highly reflects visible light, has a small variation of the reflective index by a polarization component, and highly transmits near infrared light.SOLUTION: A film satisfying all of the following conditions (1) to (3) is provided. (1) An average reflective index in a wavelength band of 400-700 nm measured at an incident angle of 12° is 70% or more, and a maximum value of the reflective index in a wavelength band of 1000 nm - 2000 nm is 15% or less. (2) In a polarization component parallel with an orientation axis of the film at each wavelength of the wavelength band of 400-700 nm measured at an incident angle of 60° and a polarization component perpendicular to it, an absolute value of a difference between the parallel polarization component and a perpendicular polarization component is 30% or less. (3) In a wavelength band of 400-1000 nm measured at an incident angle of 12°, a difference between the wavelength at the longest wavelength side having a reflective index of 60% or less and the wavelength at the longest wavelength side having a reflective index of 25% or less is 30 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a film that highly reflects visible light, has a small variation in reflectance due to a polarization component, and highly transmits near-infrared light.

  A display method using a head-up display that reflects a display image from a liquid crystal and displays a virtual image on glass is known and used for display on a windshield of an automobile, a train, an aircraft, a ship, or the like. By adopting a display system that uses a head-up display, the display can be confirmed without changing the forward field of view during driving, leading to accident prevention. As an example of the layout of the head-up display device, there is known a method in which an image emitted from a liquid crystal display device is reflected to a concave boundary through a plane mirror, and the image is enlarged on the concave boundary to display a virtual image on the windshield ( Patent Document 1). In order to increase the size of the head-up display, it is necessary to increase the size of the concave surface, but when used outdoors, the thermal energy of sunlight is aggregated into the concave mirror as the size of the concave surface increases. Since thermal energy is transmitted to the liquid crystal display device through reflection, there is a problem that leads to breakage of the liquid crystal display device due to heat.

  As a heat countermeasure for liquid crystal display devices, visible light emitted from the liquid crystal display device is highly reflected by the flat mirror, and near infrared light with a high contribution of thermal energy reflected from the concave mirror is transmitted, so that the thermal energy of sunlight is reduced. A cold mirror material that suppresses transmission to the liquid crystal display device may be used. As a cold mirror, a dielectric film having a high refractive index and a dielectric film having a low refractive index are alternately laminated, and the optical film thickness, which is the product of the refractive index and the film thickness, is controlled to cause interference. Although a reflection technique using a dielectric multilayer film technique that selectively reflects wavelengths is used, a mirror body is known (see Patent Document 2). Also, a cold mirror film composed of all polymers using a light interference multilayer film technology in which a large number of two kinds of resins having different refractive indexes are alternately laminated and a specific light is reflected by structural light interference between layers. Has been proposed (see Patent Document 3).

JP 2013-228442 A International Publication No. 2015/056752 Japanese National Patent Publication No. 8-502597

  The infrared shielding material described in Patent Document 1 has a dielectric multilayer film in which a high refractive index layer and a low refractive index layer are alternately laminated, and is desired with high wavelength selectivity by controlling the optical film thickness. The reflection band to be reflected can be highly reflected. However, in the dielectric multilayer film, when light is incident from an oblique direction, the P-polarized component and the S-polarized component, which are orthogonal components, have greatly different reflectances, and the image emitted from the liquid crystal display device is maintained and a virtual image is displayed on the windshield. However, there is a problem that the optical design of the head-up display device is complicated.

  The all-polymer cold mirror film described in Patent Document 2 has a high-refractive index resin and a low-refractive index that are alternately laminated, and has a multi-layer laminated structure of several hundred layers, so that the entire visible light band is reflected with a high reflectance. Can do. However, there is a wide reflection boundary band that has an intermediate reflectance between the high reflection band and the non-reflection band, and the high reflection in the visible light band, which is the liquid crystal display band, and the contribution of solar thermal energy. There was a problem in achieving both high transmission in the high near infrared band.

  Accordingly, the present invention is to solve the above-mentioned problems of the prior art, and to provide a film that highly reflects visible light, has a small variation in reflectance due to polarized light components, and highly transmits near-infrared light.

The present invention employs the following means in order to solve such problems. That is, the film satisfies all of the following (1) to (3).
(1) The average reflectance in the wavelength band 400-700 nm measured at an incident angle of 12 ° is 70% or more, and the maximum reflectance in the wavelength band 1000 nm-2000 nm is 15% or less.
(2) The reflectivity of the polarized light component perpendicular to the parallel polarized light component and the polarized light component perpendicular to the orientation axis of the film in each wavelength band of 400 to 700 nm measured at an incident angle of 60 °. The absolute value of the difference is 30% or less.
(3) In the wavelength band 400-1000 nm measured at an incident angle of 12 °, the difference between the wavelength on the longest wavelength side where the reflectance is 60% or less and the wavelength on the longest wavelength side where the reflectance is 25% or less is 30 nm or less. .

  According to the present invention, it is possible to obtain a film that highly reflects visible light, has a small variation in reflectance due to a polarization component, and highly transmits near-infrared light.

The figure which shows typically the design layer thickness gradient structure of Examples 1-6 and Comparative Examples 1 and 2. The figure which shows typically the design layer thickness inclination structure of Example 7. The figure which shows typically the design layer thickness inclination structure of Example 8. The figure which shows typically the design layer thickness gradient structure of Example 9. The figure which shows typically the design layer thickness inclination structure of the comparative example 3 The figure which shows typically the design layer thickness gradient structure of the comparative example 4 The figure which shows typically the design layer thickness gradient structure of the comparative example 5 An example of a configuration diagram of a feed block used in the present invention Configuration diagram of slit plate and slit Cross-sectional configuration diagram of slit

  The film of the present invention needs to have an average reflectance of 70% or more in a wavelength band of 400 to 700 nm measured at an incident angle of 12 ° determined by a measurement method described later. 75% or more is preferable, and 80% or more is more preferable. The incident angle in the present invention is an angle parallel to the film thickness direction of 0 ° and an angle perpendicular to the film thickness direction of 90 °. The reflectivity of a film using interference reflection generally tends to be higher when the incident angle is close to 90 °. Therefore, by setting the average reflectance in the wavelength band of 400 to 700 nm measured at an incident angle of 12 ° to 70% or more, a film that highly reflects at a wide angle when used as a reflective material for a liquid crystal display can be obtained. When the average reflectance in the wavelength band of 400 to 700 nm measured at an incident angle of 12 ° is less than 70%, the reflectance is low when a reflective material is used, and the reflected image may become unclear.

  The film of the present invention needs to have a maximum reflectance of 15% or less in a wavelength band of 1000 nm to 2000 nm measured at an incident angle of 12 °. 12% or less is preferable and 10% or less is more preferable. The wavelength band reflected by a film using interference reflection generally tends to reflect short wavelengths when the incident angle is close to 90 °. Therefore, by setting the maximum value of the reflectance in the wavelength band of 1000 nm to 2000 nm measured at an incident angle of 12 ° to 15% or less, the heat in the near infrared band of sunlight is wide when used as a reflective material for a liquid crystal display. It can transmit energy and suppress the transmission of thermal energy.

  The film of the present invention has a parallel polarization component perpendicular to the polarization component parallel to the orientation axis of the film at each wavelength in the wavelength band 400-700 nm measured at an incident angle of 60 °. The absolute value of the difference in reflectance needs to be 30% or less. 28% or less is preferable, and 25% or less is more preferable. Absolute difference in reflectance between the parallel polarization component and the perpendicular polarization component in the polarization component perpendicular to the alignment axis of the film at each wavelength in the wavelength band 400-700 nm measured at an incident angle of 60 ° By setting the value to 30% or less, the image emitted from the liquid crystal display device can be maintained and reflected, and the optical design of the image of the liquid crystal display can be simplified.

The film of the present invention has a difference between the wavelength on the longest wavelength side where the reflectance is 60% or less and the wavelength on the longest wavelength side where the reflectance is 25% or less (hereinafter, referred to as “wavelength band 400-1000 nm” measured at an incident angle of 12 °). The longest wavelength (referred to as λ ₆₀ -λ ₂₅ ) needs to be 30 nm or less. 25 nm or less is preferable and 20 nm or less is more preferable. The longest wavelength (λ ₆₀ −λ ₂₅ ) is the bandwidth of the boundary between the high reflection band and the non-reflection band. By setting the longest wavelength (λ ₆₀ -λ ₂₅ ) to 30 nm or less, only the band of light emitted from the liquid crystal display device can be highly reflected, and the band having thermal energy not related to the liquid crystal display light can be highly transmitted. Thus, it is possible to achieve both high reflection of the image of the liquid crystal display device and suppression of heat transfer to the liquid crystal display device.

  In the film of the present invention, the difference between the maximum value and the minimum value of the reflectance in the wavelength band 400-700 nm measured at an incident angle of 60 ° is preferably 15% or less. More preferably, it is 12% or less, More preferably, it is 10% or less. When the difference between the maximum value and the minimum value of the reflectance in the wavelength band 400-700 nm measured at an incident angle of 60 ° exceeds 15%, the display color of the liquid crystal display image is obtained when the reflective material is angled from the liquid crystal display device. May change, making it impossible to reproduce images emitted from the liquid crystal display device.

In the film of the present invention, it is preferable that the color difference ΔE of the reflected color of the D65 light source before and after the durability test is performed under the following conditions is 7 or less. More preferably, it is 5 or less. When ΔE exceeds 7, when the film is exposed to sunlight for a long time, the reflection performance of the film may be deteriorated and may not be used as a reflective material. Note that the color difference Delta] E, the difference in ^{L *} values before and after the test [Delta] L ^{*, a *} difference value Δa ^{*, b *} √ the difference value when the ^{Δb * (ΔL * 2 + Δa} * 2 + Δb * It is a numerical value indicating the magnitude of the colored change represented by ² ).
<Durability test>
The reflective film is irradiated for 462 hours at an irradiance of 180 W / m ² using a xenon lamp (manufactured by Suga Test Instruments, SC750) under the conditions of a temperature of 95 ° C. and a relative humidity of 30% RH.

In the film of the present invention, it is preferable that the color difference ΔE of the reflected color of the D65 light source before and after performing the heat resistance test under the following conditions is 7 or less. More preferably, it is 5 or less. When ΔE exceeds 7, when the state of the film being heated for a long time due to sunlight continues to be high, the reflection performance of the film may be deteriorated and may not be used as a reflector.
<Heat resistance test>
The film is heated for 90 days using a gear oven (GPHH-202, manufactured by ESPEC Corporation) under conditions of a temperature of 80 ° C. and a relative humidity of 10% RH or less.

  The film of the present invention preferably has a haze of 0.1% to 2.0%. Preferably they are 0.1% or more and 1.5% or less, More preferably, they are 0.1% or more and 1.0% or less. If the haze of the film exceeds 2.0%, the reflected light may be scattered when the image emitted from the liquid crystal display device is reflected, and the reflected image may become unclear.

  The film of the present invention has a layer composed of a thermoplastic resin A (hereinafter referred to as “A layer”) and a layer composed of a thermoplastic resin B layer containing an amorphous resin (hereinafter referred to as “B layer”) in the thickness direction. It is preferable that 200 layers or more are alternately laminated. More preferred is a structure in which 300 layers or more are alternately laminated in the thickness direction, and still more preferred is a structure in which 400 layers or more are alternately laminated in the thickness direction. In the case of a laminate of less than 200 layers, the reflection performance deteriorates, and the reflected image may become unclear when used as a reflective material for liquid crystal display.

When the film of this invention has the said laminated structure, it is preferable that the thickness of the outermost layer of both sides is 1 micrometer or more and 10 micrometers or less. More preferably, it is 2 μm or more and 7 μm or less. If the thickness is less than 1 μm, uneven stacking due to stacking failure occurs, the longest wavelength (λ ₆₀ −λ ₂₅ ) cannot be reduced, and high reflection of the liquid crystal display image and high transmission of solar heat energy cannot be achieved at the same time. There is. When the thickness exceeds 10 μm, delamination may easily occur near the surface thick film layer.

  When the film of this invention has the said laminated structure, it is preferable to have 1 or more layers whose thickness is 2 micrometers or more and 6 micrometers or less in an inner layer. More preferably, it is 3 μm or more and 4 μm or less. When both inner layers have a thickness of less than 2 μm, uneven stacking due to stacking failure occurs, making it impossible to achieve both high reflection of the liquid crystal display image and high transmission of solar heat energy. When the thickness of the inner layer exceeds 6 μm, delamination may easily occur near the inner thick film layer.

When the film according to the present invention has the above-described laminated structure, in the thin film layer having a layer thickness of less than 1 μm, the difference in thickness between adjacent layers in the A layer and the B layer is continuously monotonous within a range of 50 nm or less. It is preferable to have two or more inclined structures that increase or monotonously decrease. If it does not have an inclined structure of two or more steps, a slight stacking fault occurs in some layers, and if the thickness deviates from the design value, there is no layer of the same thickness in other parts, The difference in reflectance becomes large in the wavelength band 400-700 nm measured at an incident angle of 60 °, and when the liquid crystal display image is reflected, the liquid crystal display image is not reproduced, and the longest wavelength (λ ₆₀ -λ ₂₅ ) is set. In some cases, it cannot be made small, and high reflection of the liquid crystal display image and high transmission of solar heat energy cannot be achieved at the same time.

  The figure which shows the design layer thickness is demonstrated as an example of the preferable layer structure of the film in this invention. FIG. 1 shows a film in which layers composed of two types of thermoplastic resins (hereinafter also referred to as “resin A” and “resin B”) are alternately laminated in the thickness direction. FIG. The layer thickness corresponds only to the integer layer number in the figure, the A layer made of the crystalline thermoplastic resin A corresponds to the odd number, and the B layer made of the thermoplastic resin B containing the amorphous resin is Corresponds to an even number. The thick film layer is preferably formed of an A layer made of resin A which is a crystalline resin. The same applies to FIGS. 2 and 3. Further, in the present invention, for the sake of convenience, the layer thickness configuration of FIG. 1 is referred to as a four-step inclined structure, the layer thickness configuration of FIG. 2 is referred to as a three-step inclined structure, and the layer thickness configuration of FIG. . Here, the “four-step inclined structure” referred to in the present invention refers to a structure that can be approximated by four monotonically increasing curves and / or monotonically decreasing curves. At this time, the lamination ratio is preferably 0.7 to 1.3. The inclined structure and stacking ratio in the present invention will be described with examples. Surface layer Thick film layer A layer (layer number 1) / B layer (layer number 2) / A layer (layer number 3) / B layer (layer number 4) / A layer (layer number 5) / B layer (layer number 6) ) / A layer (layer number 7) /.../ surface layer thick film layer A layer (layer number 801) is a laminated film having a lamination ratio of 1.0 means that a pair of B layers and A layer thickness ratio (A layer (layer number 3) thickness / B layer (layer number 2) thickness, A layer (layer number 5) thickness / B layer (layer number 4) thickness, A layer (layer The thickness of number 7) / the thickness of layer B (layer number 6) is 1.0. And having an inclined structure means the sum of thicknesses of a pair of B layer and A layer (sum of thicknesses of B layer (layer number 2) and A layer (layer number 3), B layer (layer number 4) and A The sum of the layers (layer number 5) and the sum of the thicknesses of the B layer (layer number 6) and the A layer (layer number 7) are gradually increased or decreased.

Locations where the inclined structure changes from decrease to increase and from change to increase decrease are likely to cause stacking faults, causing variations in reflectance in the reflection band and the longest wavelength (λ ₆₀ −λ ₂₅ ). By providing a thick film layer having a thickness of 2 μm or more and 6 μm or less on the outermost layer on the above location and on both sides, the thick film layer can absorb the shear stress generated in the extrusion process at the time of manufacturing that causes a stacking failure. it can. When the thickness of the thick film layer is less than 2 μm, it is not possible to suppress the stacking fault because the layer configuration is changed from decrease to increase, and the absorption of shear stress due to the stacking fault at the location where the change from increase to decrease is not sufficient. Because the reflection of light at a specific wavelength is different from the design value, it is impossible to reproduce the color tone of the reflected image when reflecting the image of the liquid crystal display device, and the liquid crystal display image is clearly reflected and high transmission of solar heat energy May not be compatible. When the thick film layer exceeds 6 μm, the elastic modulus is different between the thick film layer made of the crystalline resin A and the portion other than the thick film layer. Therefore, if shear stress is applied in the thickness direction during cutting in processing, the vicinity of the thick film layer In some cases, stress is concentrated and delamination is likely to occur. FIG. 4 shows a structure in which the number of layers in FIG. 3 is 251. FIG. 5 shows a structure in which all four grades have the same layer thickness distribution. Since all the four grades have the same thickness design, FIG. 6 shows an example in which the thickness distribution of the slope is made smaller than that of the layer configuration of FIG. 4 to increase the distribution density of the layers, and the reflectance in the reflection band is high. However, the reflection band becomes narrow, and the average reflectance in the wavelength band of 400 to 700 nm measured at an incident angle of 12 ° may not be 70% or more in a film that can be produced by coextrusion. FIG. 7 shows a structure in which the number of stacked layers in FIG. 4 is 191. If the number of stacked layers is small, the average reflectance in the wavelength band 400-700 nm measured at an incident angle of 12 ° may not be 70% or more. In addition, when the film of this invention has the said laminated structure, a thick film layer means a layer whose thickness is 1.0 micrometer or more, and a thin film layer means a layer whose thickness is less than 1.0 micrometer.

When the film according to the present invention has the above-described laminated structure, the number of layers, which is the top 5% of the thickness of the thin film layer of A layer, is the number of the thin film layer of A layer from the viewpoint of narrowing the band at the boundary between the reflection band and the transmission band. It is preferable that the number of layers, which is the uppermost 5% of the thickness of the B thin film layer, is 10% or less of the total number of the B thin film layers, while being 10% or less of the total number of layers. More preferably, it is 7% or less, More preferably, it is 5% or less. In the present invention, the upper 5% layer of the A layer or B layer is the difference between the thickness of the thin film layer having the largest thickness and the thickness of the thin film layer having the smallest thickness in the thickness of the thin film layer of the A layer or B layer. Is a layer having a thickness exceeding the thickness obtained by adding 0.95 to the value obtained by adding the layer thickness of the thinnest layer. Since the layer with the uppermost 5% thickness reflects the longest wavelength side of the reflection band, the layer reflects the band at the boundary between the reflection band and the transmission band. In the case where a layer out of the design occurs in the upper 5% layer, when the same optical film thickness is distributed elsewhere, the reflection becomes stronger at a wavelength different from the desired wavelength, and the longest wavelength (λ ₆₀ −λ ₂₅ ) cannot be reduced. Even when a layer deviating from the design occurs by setting the ratio of the top 5% layer to 10% or less, the same optical film thickness is difficult to be distributed, and the longest wavelength (λ ₆₀ -λ ₂₅ ) is 30 nm or less. It can be. In the layer thickness configuration of FIG. 1, it is designed so that there is no upper 5% layer in the inclined layer thickness portions of the 1st to 201st layers and the 601st to 801th layers. It can be as follows.

  The film in the present invention is a film formed by coextrusion, and it is preferable that 200 layers or more of A layers and B layers are alternately laminated in the thickness direction. By making the film molded by coextrusion, the orientation of the film can be controlled during the production of the film, and with respect to the orientation axis of the film at each wavelength in the wavelength band 400-700 nm measured at an incident angle of 60 °. In the parallel polarization component and the perpendicular polarization component, the absolute value of the difference in reflectance between the parallel polarization component and the perpendicular polarization component can be easily reduced to 30% or less. In addition, when the layer structure has a small inclination of the inclined structure as shown in FIG. 6, a narrow reflection band can be reflected with a high reflectance and a high wavelength selectivity, but in order to achieve a wide reflection band, a thickness is required. It is necessary to bond two films having different layers with an adhesive layer such as dry laminate. However, when two films having different orientations are bonded together, the orientation cannot be controlled, and the difference in reflection performance due to the polarization component may not be reduced. In addition, when the adhesive layer is provided, the adhesive layer may be deteriorated by ultraviolet rays or heat. The color difference ΔE of the reflected color of the D65 light source before and after the durability test and the color difference ΔE of the reflected color of the D65 light source before and after the heat resistance test are obtained. It may not be possible to make it 7 or less.

  Two types of resins, a crystalline thermoplastic resin A and a thermoplastic resin B containing an amorphous resin used in the film of the present invention, may be a copolymer or a mixture of two or more resins. good. Among these, it is particularly preferable to use a polyester resin. The crystallinity here means that the heat of fusion is 5 J / g or more in differential scanning calorimetry (DSC). On the other hand, “amorphous” means that the heat of fusion is similarly less than 5 J / g.

  Examples of the thermoplastic resin used in the film of the present invention include polyester resin, polyolefin resin, polyamide resin, aramid resin, polyacetal resin, polyphenylene sulfide resin, fluororesin, polyglycolic acid resin, and polylactic acid resin. Among these, a polyester resin is preferably used in terms of strength, heat resistance, and transparency. As the polyester resin, a polyester obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol is preferable. Here, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′- Examples thereof include diphenyl dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl sulfone dicarboxylic acid, and the like. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid and ester derivatives thereof. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid having a high refractive index are preferable. Only one kind of these acid components may be used, or two or more kinds may be used in combination, and further, an oxyacid such as hydroxybenzoic acid may be partially copolymerized. Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-hexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4- Hydroxyethoxyphenyl) propane, isosorbate, spiroglycol and the like. Of these, ethylene glycol is preferably used. These diol components may use only 1 type and may use 2 or more types together.

  Among the polyesters, polyethylene terephthalate and copolymers thereof, polyethylene naphthalate and copolymers thereof, polybutylene terephthalate and copolymers thereof, polybutylene naphthalate and copolymers thereof, and polyhexamethylene terephthalate and copolymers thereof. It is preferable to use a polymer, polyhexamethylene naphthalate, a copolymer thereof, and the like.

  As a preferable combination of the resin A and the resin B selected from thermoplastic resins, it is preferable to use a resin containing the same basic skeleton as one of the resins. Here, the “basic skeleton” referred to in the present invention refers to a repeating unit constituting a resin. For example, when one resin is polyethylene terephthalate, ethylene terephthalate is the basic skeleton. Examples of the polymer include a polymer (copolymer) composed of an ethylene terephthalate unit and a cyclohexane 1,4-dimethylene terephthalate unit. As another example, when one resin is polyethylene, ethylene is a basic skeleton. When resins having the same basic skeleton are used, problems such as delamination are less likely to occur in the production of a thermoplastic resin film.

  As the crystalline thermoplastic resin A, it is preferable to use polyethylene terephthalate or polyethylene naphthalate from the viewpoints of stamping resistance (dentation resistance) and stiffness of the film itself.

  As an amorphous resin of the thermoplastic resin B containing an amorphous resin, from the viewpoint of suppressing an increase in refractive index, it contains isophthalic acid, naphthalenedicarboxylic acid, diphenyl acid, cyclohexanedicarboxylic acid, or spiroglycol, The copolymer of the resin A containing cyclohexanedimethanol, bisphenoxyethanol fluorene, and bisphenol A component is preferably mixed with the resin A or used alone. More preferably, it is a thermoplastic resin obtained by using at least spiroglycol and cyclohexanedicarboxylic acid. When the thermoplastic resin B containing an amorphous resin is a thermoplastic resin using spiroglycol and cyclohexanedicarboxylic acid, when polyethylene terephthalate or polyethylene naphthalate is used as the crystalline thermoplastic resin A, layer A Since the in-plane refractive index difference between the B layer and the B layer becomes large, it becomes easy to obtain a high reflectance. In addition, due to its strong amorphous nature, orientation crystallization during heating is unlikely to occur, and in addition to being able to reduce the color difference ΔE of the reflected color of the D65 light source before and after the heat resistance test, by adjusting the spiroglycol copolymerization ratio The glass transition temperature is increased, and the color change before and after heating can be reduced even at 80 ° C. heating.

  FIG. 8 shows an example of a feed block which is a preferred embodiment for obtaining a thermoplastic resin film having an inclined structure in the present invention. The feed block is a laminating apparatus for laminating two kinds of resins A and B, and details thereof will be described below. In FIG. 8, the member plates 6 to 16 are stacked in this order to form the feed block 17.

  The feed block 17 in FIG. 8 is derived from the resin introduction plates 7, 9, 11, 13, and 15 and has five resin introduction ports. For example, the resin A is supplied from the introduction ports 18 of the resin introduction plates 7, 11, and 15. The resin B is supplied from the introduction port 18 of the resin introduction plates 9 and 13. Then, the slit plate 8 receives the resin A from the resin introduction plate 7 and the resin B from the resin introduction plate 9, and the slit plate 10 receives the resin A from the resin introduction plate 11 and the resin B from the resin introduction plate 9. The slit plate 12 receives the resin A from the resin introduction plate 11 and the resin B from the resin introduction plate 13. The slit plate 14 receives the resin A from the resin introduction plate 15 and the resin B from the resin introduction plate 13. Will receive.

  Here, the type of resin introduced into each slit plate is determined by the positional relationship between the bottom surface of the liquid reservoir 19 in the resin introduction plates 7, 9, 11, 13 and 15 and the end of each slit in the slit plate. The That is, as shown in FIG. 8, the ridgeline 20 at the top of each slit in the slit plate is inclined with respect to the thickness direction of the slit plate (FIGS. 7B and 7C). However, as shown in FIG. 7A, the slit width for forming the thick film layer located at both ends of the slit plate is 2 from the viewpoint of preventing the thin film layer from being broken. It is necessary to be more than twice. Here, the slit width forming another thin film layer is an average value of the widths of the slit portions forming the thin film layer in at least one slit plate. More preferably, it is 3 times or more. In particular, the slit corresponding to each outermost layer portion of the film of the slit plate 8 and the slit plate 14 needs to be 10 times or more the slit width into which the resin A is introduced and other thin film layers are formed. At this time, by continuously arranging the slits into which the resin A flows, the widths can be totaled to be 10 times or more the slit width for forming another thin film layer. In this way, by providing a thick film layer at the location where the resin fed from the feed block merges and at the location where the resin block wall meets the boundary with the wall surface of the pipe, the change in the layer thickness distribution immediately after merging In addition, it is possible to prevent fluctuations in the resin speed in the multilayer flow near the piping, so that the variation in the reflectance of visible light is reduced without breaking the lamination ratio, and the high reflection of the liquid crystal display and sunlight It is possible to achieve both high thermal energy transmission. As shown in FIG. 10, the height of the bottom surface of the liquid reservoir 19 in the resin introduction plates 7, 9, 11, 13, 15 (13 and 15 are omitted from FIG. 10 because they are repetitive structures) It is located at a height between the upper end 21 and the lower end 22 of the ridge line 20. Accordingly, resin is introduced from the liquid reservoir 19 of the resin introduction plates 7, 9, 11, 13, and 15 from the side where the ridge line 20 is raised (23 in FIG. 10), but the ridge line 20 is lowered. From the side, the slit is sealed and no resin is introduced. Thus, since the resin A or B is selectively introduced for each slit, the flow of the resin having a laminated structure is the slit plates 8, 10, 12, and 14 (12 and 14 are omitted because they are repetitive structures). It is formed inside and flows out from the outlet 24 below the slit plates 8, 10, 12, 14.

  As the shape of the slit, it is preferable that the slit area on the side where the resin is introduced is not the same as the slit area on the side where the resin is not introduced. With such a structure, the flow rate distribution on the side where the resin is introduced and the side where the resin is not introduced can be reduced, so that the laminating accuracy in the width direction is improved. Further, (slit area on the side where no resin is introduced) / (slit area on the side where the resin is introduced) is preferably 0.2 or more and 0.9 or less. More preferably, it is 0.5 or less. Moreover, it is preferable that the pressure loss in a feed block will be 1 Mpa or more. Moreover, it is preferable that the slit length (the longer one of the slit lengths in the Z direction in FIG. 8) is 20 mm or more. On the other hand, the gap width of the slit is preferably 0.3 mm or more from the viewpoint of processing accuracy, more preferably 0. It is 5 mm or more and 3 mm or less.

  Thus, by adjusting the width and length of the slit, it is possible to control the thickness of each layer and obtain a thermoplastic resin film having an inclined structure. Further, in each slit, the slit gap width is preferably in the range of −3% to + 3% of the target value. More preferably, it is in the range of -2% to + 2%. When the slit gap width is in the range of −3% to + 3% of the target value, local increase / decrease in the density of the layer thickness can be prevented. Note that the slit is preferably manufactured by wire electric discharge machining from the viewpoint of requiring high machining accuracy in which the width and length are finely adjusted.

  It is also preferable to have a manifold portion corresponding to each slit plate. Because the manifold portion makes the flow velocity distribution in the width direction (Y direction in FIG. 8) inside the slit plate uniform, the lamination ratio in the width direction of the laminated films can be made uniform, and a large area film However, it becomes possible to laminate with high accuracy, and the reflectance in the film width direction can be controlled with high accuracy. Moreover, it is preferable that the 2nd manifold which has a larger dimension of a lamination direction than a slit gap | interval is provided in all the slit width directions in the part connected to each slit from the said manifold. The second manifold is preferably at least twice the slit gap. In addition, it is preferable that the second manifold is inclined in the downstream direction as it is separated from the manifold of the resin introduction plate communicating with the slit. By adopting such a structure, the molten material can easily flow into the slit far from the manifold of the resin introduction plate, and the difference in flow rate between the near side and the far side of the first manifold of the slit becomes small. The flow rate of the molten material becomes uniform. More preferably, the resin is supplied from one liquid reservoir to two or more slit plates. In this way, for example, even if there is a flow distribution in the width direction slightly inside the slit plate, because it is further laminated in the merging device described below, the lamination ratio is made uniform in total, It is possible to reduce unevenness in the high-order reflection band.

  The polymer passing through the slit is generally represented by the formula (i).

That is, assuming that the pressure in the liquid reservoir is uniform and the pressure drop ΔP is constant, the flow rate Q corresponding to one layer thickness can be easily adjusted by adjusting one slit size. it can. In this apparatus, since the thickness of each layer can be adjusted by a slit shape (length, width), it is possible to achieve an arbitrary layer thickness. For example, a method for achieving the structure as shown in FIG. 1 will be described. In this case, the slit plate has a four-plate structure, and the slit length of each slit plate has a distribution of monotonically increasing and monotonically decreasing slit lengths, and between adjacent slit plates (in this case, monotonic). Distribution of length and width of at least 10 or more slits arranged at the front and back, respectively, centering on the slits forming the thick film layer that becomes the joint of the layers at the points where the increase and decrease or monotonous decrease and increase occur) Is achieved by designing to be the same before and after.

Q: Resin flow rate t: Slit width W: Slit depth μ: Resin viscosity L: Slit length ΔP: Pressure drop The resin that flows out from each slit plate is a merging device arranged immediately below the feed block in FIG. Are merged as one laminated flow. Thereafter, the molten resin flow is filled in the manifold portion inside the T die, further widened, and then extruded into a sheet form from the die slit. At this time, the sheet width direction dimension of the arbitrary cross section perpendicular to the flow path direction in the flow path connecting the feed block and the base is W, the sheet thickness direction dimension is T, and the sheet width direction dimension of the discharge port of the base is Is Wd, and L is the minimum sheet thickness direction dimension of the outermost layer of the laminate, it is preferable that both the relations of the formulas (ii) and (iii) are satisfied.

In order to reflect only the design wavelength in the wavelength band range of 400 to 700 nm, it is necessary to design the thickness of each layer based on the following formula (iv). The thermoplastic resin film in the present invention can reflect / transmit light, but the reflectance can be controlled by the refractive index difference between the resin A and the resin B and the number of layers.
Formula (iv) 2 × (na · da + nb · db) = λ
na: In-plane average refractive index of a layer made of crystalline thermoplastic resin A nb: In-plane average refractive index of a layer made of thermoplastic resin B containing an amorphous resin da: Layer thickness of a layer made of resin A (Nm)
db: Layer thickness of the layer made of resin B (nm)
λ: main reflection wavelength (primary reflection wavelength)
The in-plane average refractive index (n _a , n _b ) of the A layer and the B layer is 5 mm (width direction) × 20 mm (longitudinal direction) × 0.5 mm (thickness direction) of a single film oriented film. It is obtained by measuring the refractive index of the film at a temperature of 23 ° C. and a wavelength of 589 nm five times with an Abbe refractometer, and calculating the average value.

  In the film of the present invention, the reflectance in the wavelength band 700-1000 nm measured at an incident angle of 12 ° is preferably highly reflected to an appropriate wavelength band depending on the reflection angle when used as a reflective material for a liquid crystal display device. In general, the wavelength band reflected by a film using interference reflection tends to reflect a low wavelength when the incident angle is close to 90 °. The reflection band changes. Since the wavelength band to be reflected can be adjusted by the thicknesses of the resin A and resin B layers as described in the formula (iv), it can be easily adjusted by changing the total thickness of the film.

  In the film of the present invention, in order to make the lamination of the resin A and the resin B as designed, it is necessary to control the uneven lamination immediately after the resin A and the resin B merge at the feed block. Resin A and Resin B merged in the feed block have different melt viscosities, so uneven stacking occurs near the interface between Resin A and Resin B, and stacking unevenness grows before the die discharges, resulting in a change in design and layer thickness. However, reflection in a desired wavelength band may not be achieved. In order to achieve high reflection, resin A may be a PET resin, and resin B may be a resin having a low refractive index copolymerized with spiroglycol (SPG) and cyclohexanedicarboxylic acid (CHDC). In a temperature range of 270 to 290 ° C., which is a high melting temperature, the melt viscosity of the resin A may be low, and shear stress caused by the viscosity difference may occur due to the distribution of shear stress in the layer of the resin B. In order to reduce the shear distribution in the layer of the resin B due to the resin A, the viscosity of the resin A is low, and by increasing the viscosity of the resin B, it is preferable because uneven lamination can be suppressed.

  In the thermoplastic resin film of the present invention, the difference between the in-plane average refractive index of the A layer of the thermoplastic resin film and the in-plane average refractive index of the B layer is preferably 0.070 or more and 0.170 or less. More preferably, it is 0.080 or more and 0.160 or less. When the difference in the in-plane average refractive index is less than 0.070, sufficient reflectance may not be obtained, and the liquid crystal display may not be clearly reflected.

  In the film of the present invention, it is preferable that an easy-adhesion layer comprising an acrylic / urethane copolymer resin and two or more kinds of crosslinking agents is provided on at least one surface of the film. When a hard coat layer is applied to a film, if an easy adhesion layer is not provided on the treated surface, the adhesion at the interface may decrease.

  As the acrylic / urethane copolymer resin constituting the easy-adhesion layer preferably used in the present invention, an acrylic monomer is, for example, an alkyl acrylate (the alkyl group is methyl, ethyl, n-propyl, n-butyl, isobutyl, t- Butyl, 2-ethylhexyl, cyclohexyl, etc.), 2-hydroxylethyl acrylate, 2-hydroxylethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and other hydroxy group-containing monomers, acrylamide, methacrylamide, N-methyl methacrylamide N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate Amino group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and other glycidyl group-containing monomers, acrylic acid, methacrylic acid and their salts (sodium salts, potassium salts, ammonium salts, etc.) carboxyl groups or monomers containing such salts, etc. Can be used. Moreover, as the urethane component in the present invention, a resin obtained by reacting a polyhydroxy compound and a polyisocyanate compound by a known urethane resin polymerization method such as emulsion polymerization or suspension polymerization can be used. Examples of the polyhydroxy compound constituting the urethane component include polyethylene glycol, polypropylene glycol, polyethylene / polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, poly Caprolactone, polyhexamethylene adipate, polyhexamethylene sebacate, polytetramethylene adipate, polytetramethylene sebacate, trimethylolpropane, trimethylolethane, pentaerythritol, polycarbonate diol, glycerin and the like can be used.

  As the crosslinking agent constituting the easy-adhesion layer in the present invention, it is preferable to copolymerize a crosslinkable functional group, for example, a melamine crosslinking agent, an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, or a methylolation. Alternatively, alkylolized urea crosslinking agents, acrylamide crosslinking agents, polyamide crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, various silane coupling agents, various titanate coupling agents, and the like can be used. Further, from the viewpoint of heat-and-moisture resistance to the hard coat layer and the silicone-based adhesive layer, it is preferable to use two or more types of crosslinking agents. Specifically, at least one of the crosslinking agents is an oxazoline-based crosslinking agent or a carbodiimide. It is preferable to use a system crosslinking agent.

  Furthermore, since only the components of the easy-adhesion layer are easily charged, as a result, foreign matters may be mixed during processing due to static electricity, resulting in a problem of appearance defects. Therefore, it is preferable that the component of the easily adhesive layer contains a conductive polymer from the viewpoint of antistatic. As the conductive polymer, polypyrrole, polyaniline, polyacetylene, polythiophene vinylene, polyphenylene sulfide, poly-p-phenylene, polyheterocycle vinylene, particularly preferably (3,4-ethylenedioxythiophene) (PEDOT) is there.

  By providing a hard coat layer on the surface of the thermoplastic resin film of the present invention, it is possible to prevent the film from being damaged and to impart scratch resistance. However, for applications that do not require a hard coat layer in terms of cost, it is not always necessary to provide a hard coat layer.

  As the hard coat layer, for example, acrylic resins, urethane resins, melamine resins, organic silicate resins, silicone resins, and the like can be used. Among these, from the viewpoints of hardness, durability and productivity, silicone resins and acrylic resins are preferable, acrylic resins are more preferable, and active ray curable acrylic resins are most preferable.

  In the composition of the hard coat layer, various additives can be blended as necessary within a range not impairing the effects of the present invention. For example, stabilizers such as antioxidants, light stabilizers, ultraviolet absorbers, surfactants, leveling agents, antistatic agents, and the like can be used. The thickness of the hard coat layer in the present invention is determined according to the use, but is usually preferably 0.1 μm or more and 30 μm or less, and more preferably 1 μm or more and 15 μm or less. When the thickness of the hard coat layer is less than 0.1 μm, even if the composition of the hard coat layer is sufficiently cured, the film thickness is too thin, so that the surface hardness is low and the surface may be easily damaged. When the thickness of the hard coat layer exceeds 30 μm, the cured film may easily crack due to stress such as bending.

  Next, although an example of the preferable manufacturing method of the film of this invention is demonstrated below, it is not restrict | limited by this.

  First, two types of resins A and B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to each of two extruders. In each extruder, the resin melted by heating to a temperature equal to or higher than the melting point makes the amount of resin extruded uniform with a gear pump or the like, and removes foreign matter or modified resin through a filter or the like. Resin A and resin B sent out from different flow paths using two extruders are sent into the multilayer laminating apparatus. As a multilayer laminating apparatus, it is desirable to use a feed block including at least two members having a large number of fine slits separately. When such a feed block is used, the apparatus does not become extremely large, so that foreign matter due to thermal deterioration is small, and even when the number of layers is extremely large, it is possible to stack with high accuracy. Also, the stacking accuracy in the width direction is significantly improved as compared with the prior art. It is also possible to form an arbitrary layer thickness configuration.

  When the inclined structure has two or more steps, the change from the thin layer to the thick layer or the change in the layer thickness from the thick layer to the thin layer becomes very steep. In the present invention, a feed block including at least two members having a large number of fine slits is used. However, the layer thickness distribution changes immediately after merging at the location where the resin fed from this separate feed block merges, which is a major cause of variation from reflection in the desired wavelength band. Therefore, it is necessary to adjust the flow rate so that the lamination ratio becomes 0.7 to 1.3 so that the flow rate of the resin A and the resin B does not change greatly in the portion corresponding to the layer having a thickness of 1 μm or less in the laminated film. It is. In addition, the resin A has a low viscosity and the resin B has a high viscosity so that the unevenness of the lamination is small so that the resin B, which has a higher viscosity than the resin A in the molten state, does not generate distortion due to the shear stress difference in the layer. Thus, a desired layer thickness distribution is obtained. Furthermore, since the resin speed near the pipe decreases due to the influence of the wall surface of the pipe in the path from the feed block to the base, the film lamination accuracy is further deteriorated due to the difference in flow velocity between the pipe wall surface and the pipe center. Therefore, by replacing a certain distance between the resin outermost layer part and the resin merging part of the separate feed block with the same polymer, a thermoplastic resin having a narrow wavelength band in which rise and fall of reflection are narrow without breaking the lamination ratio A film can be obtained. At this time, when the outermost thick film layer on both sides of the laminated film is the resin A, the layer made of the resin A corresponds to the outer thick film layer (the outermost layer on both sides). Moreover, it is preferable that the resin used for the inner thick film layer is a highly crystalline resin in order to improve the anti-scratch resistance. If the inner thick film layer is less than 2 μm, the suppression of the change in the layer thickness distribution at the merging portion is not sufficient, and it is necessary that the thickness is 2 μm or more. In adjusting the thickness of the thick film layer, it is preferable to adjust each flow rate corresponding to the thickness of the corresponding layer by the gap between the slits. In this case, the gap accuracy of each slit gap is preferably ± 10 μm or less. By using such a special feed block, it is possible to obtain a thermoplastic resin film that forms an inclined structure of two or more stages with high accuracy.

  The molten laminate formed in the desired layer configuration in this way is then formed into a desired shape with a die and then discharged. And the sheet | seat laminated | stacked in the multilayer discharged | emitted from die | dye is extruded on rotary cooling bodies, such as a casting drum, and is cooled and solidified, and a casting film (non-stretched film) is obtained. At this time, it is preferable to use a wire-like, tape-like, wire-like, or knife-like electrode to be brought into close contact with a rotating cooling body such as a casting drum by an electrostatic force and rapidly solidify. Also preferred is a method in which air is blown out from a slit-like, spot-like or planar device and brought into close contact with a rotating cooling body such as a casting drum, or rapidly cooled and solidified by being brought into close contact with the rotating cooling body with a nip roll.

  The casting film (unstretched film) thus obtained is preferably biaxially stretched as necessary. Biaxial stretching refers to stretching in the longitudinal direction and the width direction. Stretching may be performed sequentially in biaxial directions or simultaneously in two directions. Further, the film may be re-stretched in the longitudinal direction and / or the width direction. In particular, in the present invention, it is preferable to use simultaneous biaxial stretching from the viewpoint of suppressing in-plane orientation differences and from the viewpoint of suppressing surface scratches.

  First, the case of sequential biaxial stretching will be described. Here, the stretching in the longitudinal direction refers to stretching for imparting molecular orientation to the film in the longitudinal direction. Usually, the stretching is performed by a difference in the peripheral speed of the roll. You may carry out in multiple steps using a roll pair of books. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for a thermoplastic resin film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature of the resin which comprises a thermoplastic resin film-glass transition temperature +100 degreeC is preferable.

  When providing an easily bonding layer in the thermoplastic resin film of this invention, the method of coating and laminating | coating a coating agent is preferable. As a method of coating the coating agent, a method of coating in a process separate from the polyester film manufacturing process in the present invention, a so-called off-line coating method, and an easy adhesion by performing coating during the polyester film manufacturing process of the present invention. There is a so-called in-line coating method in which the layers are laminated at once. It is preferable to adopt an in-line coating method from the viewpoint of cost and uniform coating thickness, and the solvent of the coating liquid used in that case is preferably an aqueous system from the viewpoint of environmental pollution and explosion-proof property, and water is used. It is the most preferred embodiment to use.

  When laminating the easy-adhesion layer by in-line coating, a coating material that forms the easy-adhesion layer is continuously applied to the uniaxially stretched polyester film. As a coating method of a coating (water-based coating) using water as a solvent, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

  Before applying the water-based coating, it is preferable to subject the surface of the polyester film to a corona discharge treatment or the like. This is because the adhesion between the polyester film and the coating material is improved and the coating property is also improved.

  The easy-adhesive layer has a crosslinking agent, antioxidant, heat-resistant stabilizer, anti-glare stabilizer, ultraviolet absorber, organic easy-to-lubricant, pigment, dye, organic or inorganic as long as the effect of the invention is not impaired. You may mix | blend particle | grains, a filler, surfactant, etc.

  Subsequent stretching in the width direction refers to stretching for imparting molecular orientation in the width direction of the film, usually using a tenter, transporting the film while holding both ends with clips, and applying heat to the film. After preheating, the film is stretched in the width direction. The aqueous coating applied just before the tenter is dried during this preheating. The stretching ratio varies depending on the type of resin, but usually 2 to 15 times is preferable, and 2 to 7 times is particularly preferable when polyethylene terephthalate is used for any of the resins constituting the polyester film in the present invention. . Also, in order to reduce the difference in reflectance between the component parallel to the film orientation axis and the component perpendicular to the film orientation axis at an incident angle of 60 °, the difference in the draw ratio between the longitudinal direction and the width direction is reduced so that the in-plane orientation difference is reduced. Is preferably 1.0 times or less, and more preferably 0.8 times or less. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises the polyester film in this invention are preferable. The biaxially stretched polyester film is preferably subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter in order to impart flatness and dimensional stability. After being heat-treated in this way, it is gradually cooled gradually, cooled to room temperature, and wound up by a winder. Moreover, you may use a relaxation process etc. together in the case of annealing from heat processing as needed.

  Next, the case of simultaneous biaxial stretching will be described. In the case of simultaneous biaxial stretching, the coating material which comprises an easily bonding layer is apply | coated continuously to the obtained cast film. As a coating method of a coating (water-based coating) using water as a solvent, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

  Before applying the aqueous coating material, it is preferable to subject the surface of the thermoplastic resin film in the present invention to corona discharge treatment or the like. This is because the adhesion between the polyester film and the coating material is improved and the coating property is also improved. Next, the cast film (non-stretched film) coated with the coating agent is guided to the simultaneous biaxial tenter, and conveyed while holding both ends of the film with clips, and stretched in the longitudinal and width directions simultaneously and / or stepwise. To do. As simultaneous biaxial stretching machines, there are pantograph method, screw method, drive motor method, linear motor method, but it is possible to change the stretching ratio arbitrarily and drive motor method that can perform relaxation treatment at any place or A linear motor system is preferred. The stretching magnification varies depending on the type of resin, but usually, the area magnification is preferably 6 to 50 times, and the area magnification is particularly preferably 8 to 30 times. In particular, in the case of simultaneous biaxial stretching, in order to reduce the difference in reflectance between the component parallel to and perpendicular to the film orientation axis at an incident angle of 60 °, the longitudinal direction is reduced so that the in-plane orientation difference is reduced. And the difference in the draw ratio in the width direction is preferably 1.0 times or less, more preferably 0.5 times or less. In addition, it is preferable that the stretching speeds in the longitudinal direction and the width direction are substantially equal. Moreover, as extending | stretching temperature, the glass transition temperature of the resin which comprises a polyester film-glass transition temperature +120 degreeC is preferable. The biaxially stretched film is preferably subsequently subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter in order to impart flatness and dimensional stability. In this heat treatment, in order to suppress the distribution of the main orientation axis in the width direction, it is preferable to perform a relaxation treatment instantaneously in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone. After being heat-treated in this way, it is gradually cooled gradually, cooled to room temperature, and wound up by a winder. Moreover, you may perform a relaxation | loosening process in a longitudinal direction and / or the width direction at the time of annealing from heat processing as needed. It is preferable to perform relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone.

  The film of the present invention thus obtained highly reflects visible light, has little variation in reflectivity due to polarization components, and highly transmits near-infrared light. Therefore, an image emitted from a liquid crystal display device as a reflective material has a good appearance. Since it reflects and can suppress transmission of solar heat to the liquid crystal display device, it can be suitably used as a reflective material for a head-up display device for vehicles such as automobiles, trains, airplanes and ships.

  EXAMPLES Hereinafter, although this invention is demonstrated along an Example, this invention is not restrict | limited by these Examples. Various characteristics were measured by the following methods.

(1) Layer structure and layer thickness of film Using a transmission electron microscope (H-7100FA type, manufactured by Hitachi, Ltd.) with a sample cut out by a microtome, the cross section of the film was measured at an acceleration voltage of 75 kV. The film was observed at a magnification of 1,000,000, and the cross-sectional portion was photographed to measure the layer structure and the layer thickness. Moreover, the total thickness of each layer was made into the laminated film whole thickness. In order to obtain a high contrast, the sample was stained with RuO ₄ .

  A specific method for obtaining the layer structure and layer thickness of the film will be described. About 40,000 times TEM photographs were captured with CanonScan D123U (manufactured by Canon Inc.) at an image size of 729 dpi. The image was saved in JPEG format, and then the JPEG file was opened and image analysis was performed using image processing software (sales company Planetron Co., Ltd., Imagc-Pro Plus ver. 4). In the image analysis processing, in the vertical thick profile mode, the relationship between the average brightness in the region sandwiched between the two lines in the thickness direction and the width direction was read as numerical data. Using spreadsheet software (Excel2010), the position (nm) and brightness data were sampled in sampling step 1 (thinning 1) and subjected to numerical processing of a 5-point moving average. Furthermore, the data obtained by periodically changing the brightness is differentiated, and the maximum and minimum values of the differential curve are read by a VBA (Visual Basic For Applications) program. Calculated as the layer thickness. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated. Of the obtained layer thickness, the thin film layer was a layer having a thickness of less than 1 μm. A group in which the thickness difference between adjacent layers in the A layer and the B layer is continuously monotonously increasing or monotonically decreasing in a range of 50 nm or less is defined as an inclined structure. The inclined structure has a positive or negative inclination in which the square of R becomes 0.90 or more when the relation between the layer number and the layer thickness of each of the A layer and the B layer is approximated by least squares. The four-stage tilt structure, the configuration in FIG. 2 is called a three-stage tilt structure, and the configuration in FIG. 3 is called a two-stage tilt structure.

(2) Ratio of layer with 5% of uppermost thicknesses (1) In the thickness of the thin film layer of B layer calculated by the layer structure and layer thickness of the film, the difference between the maximum thickness and the thinnest thickness of layer B is 0. The number of layers having a thickness exceeding the thickness obtained by adding the thinnest thickness of the B layer to the thickness multiplied by 95 was calculated. The calculated number of layers was divided by the total number of B layers, and the number multiplied by 100 was taken as the proportion of the top 5% layers.

(3) Incident angle 12 ° Wavelength 400-700 nm average reflectance A sample of 5 cm square was cut out from the film. Subsequently, the relative reflectance in incident angle (PHI) = 12 was measured using the spectrophotometer (The Hitachi, Ltd. make, U-4100 Spectrophotometer). The inner wall of the attached integrating sphere is barium sulfate, and the standard plate is aluminum oxide. The measurement wavelength was 250 nm to 2000 nm, the slit was 2 nm (visible) / automatic control (infrared), the gain was set to 2, and the measurement was performed at a scanning speed of 600 nm / min. The back of the sample was painted black with oil-based ink. Next, the average reflectance in the wavelength band of 400 to 700 nm was calculated. The average reflectance is calculated by calculating the area surrounded by the reflection curve and the wavelength band based on the Simpson method formula using the absolute reflectance data for each wavelength of 1 nm, and dividing by the wavelength band width of 300 nm. Thus, an average reflectance of an incident angle of 12 °, a wavelength of 400 to 700 nm was obtained. A detailed explanation of the Simpson method is described in “Numerical calculation method I for electronic computers” (Baifukan) (1965) by Jiro Yamauchi et al.

(4) Incidence angle 12 ° wavelength 1000-2000 nm maximum reflectance In the relative reflectance measured in (3), the maximum value of relative reflectance at wavelength 1000-2000 nm was defined as the incident angle 12 ° wavelength 1000-2000 nm maximum reflectance. .

(5) Incident angle 12 ° longest wavelength (λ ₆₀ -λ ₂₅ )
In the relative reflectance measured in (3), λ _{60 is} the wavelength at which the reflectance is 60% or less on the longest wavelength side in the wavelength band 400 nm to 1000 nm, and λ is the wavelength at which the reflectance is 25% or less on the longest wavelength side. _25, and the wavelength bandwidth of λ ₆₀ -λ _{25 is} the longest wavelength (λ ₆₀ -λ ₂₅ ) at an incident angle of 12 °.

(6) Incident angle 60 ° Maximum value of reflectance | parallel polarization component−vertical polarization component | A sample 5 cm square was cut out from the center of the alignment axis direction on the line segment having the maximum length in the alignment axis direction from the film. Next, the measurement was performed with a basic configuration using an integrating sphere attached to a spectrophotometer (U-4100 Spectrophotometer, manufactured by Hitachi, Ltd.) with reference to an auxiliary white plate of aluminum oxide attached to the apparatus. The sample was placed behind the integrating sphere with the film orientation axis direction vertical. In addition, the attached polarizer manufactured by Grantera Co., Ltd. was installed, and linearly polarized light with the polarization component polarized at 0 and 90 ° was incident. The measurement wavelength was 250 nm to 1200 nm, the slit was 2 nm (visible) / automatic control (infrared), the gain was set to 2, and the reflectance at a scanning speed of 600 nm / min and an incident angle of 60 ° was obtained. For each wavelength in the wavelength band of 400 to 700 nm, the absolute value of the difference in reflectance between 0 and 90 ° is calculated for the polarization component, and the largest value is calculated as the incident angle of 60 ° reflectance | parallel polarization component−vertical polarization component | Maximum value.

(7) Incident angle 60 ° Reflectance of wavelength 400 to 700 nm (maximum value-minimum value)
The average value of each wavelength of the polarization components 0 ° and 90 ° at an incident angle of 60 ° measured in (5) was calculated in the wavelength band of 400 to 700 nm, and the reflectance was 60 ° for each incident. The maximum value and minimum value of the reflectance at an incident angle of 60 ° in the wavelength band of 400 to 700 nm are extracted, and the difference between the maximum value and the minimum value is determined as the reflectance (maximum value−minimum value) of the incident angle of 60 ° wavelength 400 to 700 nm. did.

(8) Color difference ΔE after endurance test
A 5 cm square sample was cut from the film. Using a spectrocolorimeter (manufactured by Konica Minolta Sensing Co., Ltd., CM-3600d), the color tones L ^* , a ^* , b ^* in each sample were measured, and the average value of n number 5 was calculated. The color tone was set to L ₁ ^* , a ₁ ^* , b ₂ ^* .

In addition, as a means of measurement, after performing zero configuration of reflectance in the zero configuration box attached to the spectrocolorimeter, then performing 100% calibration using the attached white calibration plate, the film was subjected to the following conditions. L ₁ ^* , a ₁ ^* , and b ₁ ^* were measured.
Mode: Reflection, SCI / SCE simultaneous calibration Measurement diameter: 8mm
Sample: Black ink is applied to the non-measurement side Light source: D65
A durability test was performed on the measured samples under the following conditions.
<Durability test>
The film is irradiated for 462 hours at an irradiance of 180 W / m ² using a xenon lamp (SC750, SC750) under conditions of a temperature of 95 ° C. and a relative humidity of 30% RH.

The color tone of the film subjected to the durability test was measured in the same manner as before the durability test, and L ₂ ^* , a ₂ ^* , and b ₂ ^* were measured. The color difference ΔE after the durability test was determined from L ^* , a ^* , and b ^* before and after the test. The definition of the color difference ΔE after the durability test is as follows.

ΔE = ((L ₁ ^* −L ₂ ^* ) ² + (a ₁ ^* −a ₂ ^* ) ² + (b ₁ ^* −b ₂ ^* ) ² ) ^1/2
(9) Color difference ΔE after heat test
Similarly to (8), a 5 cm square sample was cut out from the film. Using a spectrocolorimeter (Konica Minolta Sensing Co., Ltd., CM-3600d), the color tone L ^* , a ^* , b ^* in each sample was measured, and the average value of n number 5 was calculated. The color tone was set to L ₁ ^* , a ₁ ^* , b ₂ ^* . The measurement was performed in the same manner as (8) color difference ΔE after the durability test.

A heat resistance test was performed on the sample under measurement under the following conditions.
<Heat resistance test>
The film is heated for 90 days using a gear oven (Espec Corp., GPHH-202) under conditions of a temperature of 80 ° C. and a relative humidity of 10% RH or less.

The color tone of the film subjected to the heat test was measured in the same manner as before the heat test, and L ₃ ^* , a ₃ ^* , and b ₃ ^* were measured. The color difference ΔE after the heat test was determined from L ^* , a ^* , and b ^* before and after the test. The definition of the color difference ΔE after the heat test is as follows.

ΔE = ((L ₁ ^* −L ₃ ^* ) ² + (a ₁ ^* −a ₃ ^* ) ² + (b ₁ ^* −b ₃ ^* ) ² ) ^1/2
(10) Haze was 23 ° C. and relative humidity was 65%, using a turbidimeter NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd. The average value measured three times was taken as the haze value.

(11) Liquid crystal display high reflectivity (3) Incident angle 12 ° Evaluation was made based on the following criteria from the measurement results of average reflectance of wavelength 400-700 nm.
○: Incident angle 12 ° Wavelength 400-700 nm Average reflectance is 75% or more Δ: Incident angle 12 ° Wavelength 400-700 nm Average reflectance is 70% or more and less than 75% ×: Incident angle 12 ° Wavelength 400-700 nm Average reflectance Is less than 70%.

(12) Color change after reflection on liquid crystal display (7) Incident angle 60 ° Evaluation was made according to the following criteria from the measurement result of reflectance (maximum value-minimum value) at a wavelength of 400 to 700 nm.
○: Incident angle 60 ° Reflectance (maximum value-minimum value) of wavelength 400 to 700 nm is 12% or less Δ: Incidence angle 60 ° Reflectance (wavelength value-minimum value) of wavelength 400-700 nm exceeds 12% 15% or less x: incident angle 60 ° Reflectance (maximum value-minimum value) of wavelengths 400 to 700 nm exceeds 15%.

(13) Reflection polarization stability of liquid crystal display (5) Incident angle 60 ° From the measurement result of the maximum value of reflectance | parallel polarization component−vertical polarization component |
○: Maximum angle of incidence angle 60 ° reflectivity | parallel polarization component−vertical polarization component | is 28% or less △: Maximum value of incidence angle 60 ° reflectance | parallel polarization component−vertical polarization component | exceeds 28% 30% or less x: incident angle 60 ° The maximum value of reflectance | parallel polarized light component−vertical polarized light component | exceeds 30%.

(14) Thermal insulation (4) Incident angle 12 ° Wavelength 1000-2000 nm Maximum reflectance and (6) Incident angle 12 ° The longest wavelength (λ ₆₀ -λ ₂₅ ) was measured according to the following criteria.

○: Incident angle 12 ° Wavelength 1000-2000 nm Maximum reflectance is 15% or less, Incident angle 12 ° Longest wavelength (λ ₆₀ -λ ₂₅ ) is 30 nm or less Δ: Incident angle 12 ° Wavelength 1000-2000 nm Maximum reflectance The maximum wavelength (λ ₆₀ -λ ₂₅ ) exceeds 30 nm with an incident angle of 12 ° and a maximum reflectance of more than 15%.

(15) Durability (8) From the measurement result of the color difference ΔE after the durability test, the following criteria were used for evaluation.
○: Color difference after endurance test is 5 or less Δ: Color difference after endurance test exceeds 5 and 7 or less ×: Color difference after endurance test exceeds 7

(16) Heat resistance (9) From the measurement result of the color difference ΔE after the heat test, the evaluation was made according to the following criteria.
○: Color difference after the heat test is 5 or less Δ: Color difference after the heat test exceeds 5 and 7 or less ×: Color difference after the heat test exceeds 7

(material)
(Resin A-1)
To a mixture of 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, 0.09 parts by weight of magnesium acetate and 0.03 parts by weight of antimony trioxide are added with respect to the amount of dimethyl terephthalate, and the temperature is raised by a conventional method. Then, a transesterification reaction is performed. Subsequently, 0.020 part by weight of 85% aqueous solution of phosphoric acid is added to the transesterification reaction product with respect to the amount of dimethyl terephthalate, and then transferred to a polycondensation reaction tank. Furthermore, the reaction system was gradually depressurized while being heated and heated, and a polycondensation reaction was carried out by a conventional method at 290 ° C. under a reduced pressure of 1 mmHg. Polyethylene terephthalate (hereinafter referred to as PET) having an intrinsic viscosity (IV) of 0.63. Got).

(Resin A-2)
Polymerization was carried out in the same manner as Resin A-1, except that a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol was used. , Sometimes referred to as PEN).

(Resin B-1)
Polyethylene terephthalate and resin A having an intrinsic viscosity (IV) of 0.60, copolymerized with 21 mol% of spiroglycol (SPG) with respect to the entire diol component and 24 mol% of cyclohexanedicarboxylic acid (CHDC) with respect to the entire dicarboxylic acid component Copolymerized polyethylene terephthalate mixed with -1 at 9: 1.

(Resin B-2)
A copolymerized polyethylene terephthalate in which polyethylene terephthalate having an intrinsic viscosity (IV) of 0.75, 30 mol% of cyclohexanedimethanol (CHDM) copolymerized with respect to the whole diol component, and resin A-1 are mixed at a ratio of 4: 1.

(Resin B-3)
Polyethylene terephthalate and resin A having an intrinsic viscosity (IV) of 0.60 copolymerized with 31 mol% of spiroglycol (SPG) with respect to the whole diol component and 24 mol% with respect to the whole dicarboxylic acid component of cyclohexanedicarboxylic acid (CHDC) Copolymerized polyethylene terephthalate mixed with -1 at 9: 1.

(Resin B-4)
Polyethylene terephthalate and resin A having an intrinsic viscosity (IV) of 0.60, copolymerized with 11 mol% of spiroglycol (SPG) with respect to the entire diol component and 24 mol% with respect to the entire dicarboxylic acid component of cyclohexanedicarboxylic acid (CHDC) Copolymerized polyethylene terephthalate mixed with -1 at 9: 1.

(Composition of easy-adhesion layer-I)
-Aqueous dispersion of acrylic / urethane copolymer resin (a): Sannaron WG658 (solid content concentration 30% by weight), manufactured by Sannan Synthetic Chemical Co., Ltd.
-Aqueous dispersion of isocyanate compound (b): “Elastoron (registered trademark)” E-37 (solid content concentration: 28% by weight) manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
-Aqueous dispersion of epoxy compound (c): manufactured by DIC Corporation, CR-5L (solid content concentration: 100% by weight)
An aqueous dispersion of the composition (d) comprising a compound having a polythiophene structure and a compound having an anion structure (solid content concentration: 1.3% by weight)
-Aqueous dispersion of oxazoline compound (e): Nippon Shokubai Co., Ltd., “Epocross (registered trademark)” WS-500 (solid content concentration 40 wt%)
-Aqueous dispersion of carbodiimide compound (f): “Carbodilite (registered trademark)” V-04 (solid content concentration 40%) manufactured by Nisshinbo Co., Ltd.
Silica particles (g): “Spherica (registered trademark)” slurry 140 (solid content concentration 40%) manufactured by JGC Catalysts & Chemicals Co., Ltd.
-Acetylene diol-based surfactant (h): manufactured by Nissin Chemical Co., Ltd., "Orphine (registered trademark)" EXP4051 (solid content concentration 50%)
-Aqueous solvent (i): pure water The above-mentioned (a) to (h) in terms of solid weight ratio (a) / (b) / (c) / (d) / (e) / (f) / ( g) / (h) = 100/100/75/25/60/60/10/15 and mixed so that the solid content concentration of the aqueous coating material is 3% by weight. Mix and adjust the concentration.

Example 1
After the resin A-1 and the resin B-1 are melted at 280 ° C. by separate twin-screw extruders with vents, four members each having 200 slits are separately provided through a gear pump and a filter. They were merged in a feed block of 801 layers. At this time, each slit width in the slit plate of the feed block was in the range of −3% to + 3% of the target value. The outermost layers on both sides to be the thick film layer are resin A-1, the resin A-1 and the resin B-1 are alternately laminated, and the layer made of the adjacent resin A-1 is made of the resin B-1. The stacking ratio divided by the layer thickness was set to 1.00. Subsequently, it extruded from the die slit into a sheet form. At this time, the sheet width direction dimension W of the arbitrary cross section perpendicular to the channel direction in the channel connecting the feed block and the die is 190 mm, the sheet thickness direction dimension T is 32 mm, and the sheet width direction dimension of the discharge port of the die. Wd was 950 mm, and the minimum sheet thickness direction dimension L of the outermost layer of the laminate was 12.4 mm. Next, it was brought into close contact with a casting drum maintained at a surface temperature of 25 ° C. by electrostatic application, and rapidly cooled and solidified to obtain a cast film.

  The obtained cast film was heated with a roll group set at 80 ° C., then stretched 3.3 times in the longitudinal direction while rapidly heating from both sides of the stretch section with a radiation heater between 100 mm in length, and then cooled once. Thus, a uniaxially stretched film was obtained. Subsequently, both surfaces of the uniaxially stretched film were subjected to corona discharge treatment in the air, the coating tension of the film was 55 mN / m, and composition-I of the easy adhesion layer was applied to both surfaces of the film with a # 4 metabar.

  The obtained uniaxially stretched film was guided to a tenter, and after preheating with 100 ° C hot air, it was stretched 3.5 times in the transverse direction at a temperature of 120 ° C. The stretched film is directly heat-treated with hot air at 240 ° C. in the tenter, then subjected to a relaxation treatment of 7% in the width direction at the same temperature, then cooled to room temperature and wound up with a winder. An axially stretched film was obtained. The total film thickness of the obtained biaxially stretched laminated film was 76 μm. The inclined structure of this laminated film is as shown in FIG. 1 (note that FIG. 1 shows that the lamination ratio exceeds 1.0, but in the case of Example 1 where the lamination ratio is 1.0, FIG. The dotted lines 4 and 5 overlap each other and have a four-step inclined structure), and the layer thickness of each layer was controlled by adjusting the slit gap. A cross section in the thickness direction of the laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thicknesses of the layer number 1 and the layer number 801 that are the outermost layers were all 4 μm, and the layer numbers 201, 401, and 601 composed of the resin A-1 were 3 μm. The properties and evaluation results of this film are shown in Table 1.

(Example 2)
A film was obtained in the same manner as in Example 1 except that the resin A-1 was changed to the resin A-2 to adjust the thickness, and the total film thickness was 72 μm. The results are shown in Table 1.

(Example 3)
The lamination ratio obtained by changing the resin B-1 to the resin B-2 and dividing the adjacent resin A-1 layer by the layer thickness of the resin B-1 layer is changed to 0.67 to adjust the thickness. A laminated film for molding was obtained in the same manner as in Example 2 except that the total film thickness was 72 μm. The results are shown in Table 1.

Example 4
The lamination ratio obtained by dividing the layer made of the adjacent resin A-1 by the layer thickness of the layer made of the resin B-1 was changed to 1.00 to adjust the thickness, and the thickness of the entire film was set to 70 μm. Similarly, a laminated film for molding was obtained. The results are shown in Table 1.

(Example 5)
A film was obtained in the same manner as in Example 1 except that the resin B-1 was changed to the resin B-3 to adjust the thickness, and the total film thickness was 76 μm. The results are shown in Table 1.

(Example 6)
A film was obtained in the same manner as in Example 5 except that the resin B-3 was changed to the resin B-4 to adjust the thickness, and the total film thickness was 77 μm. The results are shown in Table 1.

(Example 7)
The layer design of the film was changed as shown in FIG. 2 to adjust the thickness by changing the slit shape of the feed block, and the film was obtained in the same manner as in Example 1 except that the total film thickness was set to 74 μm. Show.

(Example 8)
A film was obtained in the same manner as in Example 1 except that the thickness of the film was changed by changing the slit shape of the feed block so that the layer design was as shown in FIG. The results are shown in Table 1.

Example 9
A film was obtained in the same manner as in Example 2 except that the thickness of the film was designed by changing the slit shape of the feed block so that the layer design was as shown in FIG. The results are shown in Table 1.

(Comparative Example 1)
A film was obtained in the same manner as in Example 1 except that the resin B-1 was changed to the resin B-2 to adjust the thickness, and the total film thickness was 77 μm. The results are shown in Table 1. Since there was no wavelength having a reflectance exceeding 60% in the wavelength band of 400 nm to 1000 nm, the longest wavelength (λ ₆₀ −λ ₂₅ ) of incident angle 12 ° could not be calculated.

(Comparative Example 2)
A film was obtained in the same manner as in Example 1 except that the thickness was adjusted and the total film thickness was 100 μm. The results are shown in Table 1.

(Comparative Example 3)
A film was obtained in the same manner as in Example 1 except that the thickness of the film was designed by changing the slit shape of the feed block so as to be as shown in FIG. The properties and evaluation results of this film are shown in Table 1.

(Comparative Example 4)
A film with a different thickness is obtained in the same manner as in Example 1 except that the thickness of the film is designed by changing the slit shape of the feed block so that the layer design of the film is as shown in FIG. 6, and the total film thickness is 70 μm and 50 μm. It was.

The following urethane-based thermosetting adhesive was applied to the layer number 549 side of the obtained 70 μm film at a wet thickness of 5 g / m ² , dried at a drying temperature of 70 ° C. to 90 ° C. at a speed of 20 m / min, and then a 50 μm film was formed. Using the nip roll at a nip pressure of 0.4 MPa and a temperature of 40 ° C., bonding was performed to obtain a target film. The thickness of the obtained film was 125 μm, and the number of laminated layers including the adhesive layer was 1099 layers. The properties of the obtained film are shown in Table 1.

<Adhesive>
5 parts by weight of urethane prepolymer solution “Takenate A-971” manufactured by Mitsui Chemicals Polyurethane Co., Ltd. and 0.5 part by weight of urethane prepolymer solution “Takelac A-3” manufactured by Mitsui Chemicals Polyurethane Co., Ltd. are dissolved in 5 parts by weight of ethyl acetate. Used.

(Comparative Example 5)
A film was obtained in the same manner as in Example 2 except that the thickness of the film was designed by changing the slit shape of the feed block so that the layer design was as shown in FIG. The properties and evaluation results of this film are shown in Table 1.

  The film of the present invention reflects visible light highly, has a small variation in reflectance due to polarization components, and highly transmits near-infrared light. Therefore, it reflects an image emitted from a liquid crystal display device as a reflective material with a good appearance. Since the transmission of solar heat to the display device can be suppressed, it can be suitably used as a reflective material for a head-up display device for vehicles such as automobiles, trains, airplanes and ships.

1: Layer number 2: Layer thickness 3: Thick film layer 4: Layer thickness distribution of layer A 5: Layer thickness distribution of layer B 6: Member plate 7: Resin introduction plate 8: Slit plate 8a: Slit into which resin A flows 8b: Slit into which resin B flows 9: Resin introduction plate 10: Slit plate 11: Resin introduction plate 12: Slit plate 13: Resin introduction plate 14: Slit plate 15: Resin introduction plate 16: Member plate 17: Feed block 18: Inlet 19: Liquid reservoir 20: Ridge line at the top of each slit 21: Upper end part of the ridgeline at the top part of each slit 22: Lower end part of the ridgeline at the top part of each slit 23: Resin 24 introduced into the slit 24: Outlet

Claims (7)

A film satisfying all of the following (1) to (3).
(1) The average reflectance in the wavelength band 400-700 nm measured at an incident angle of 12 ° is 70% or more, and the maximum reflectance in the wavelength band 1000 nm-2000 nm is 15% or less.
(2) The reflectivity of the polarized light component perpendicular to the parallel polarized light component and the polarized light component perpendicular to the orientation axis of the film in each wavelength band of 400 to 700 nm measured at an incident angle of 60 °. The absolute value of the difference is 30% or less.
(3) In the wavelength band 400-1000 nm measured at an incident angle of 12 °, the difference between the wavelength on the longest wavelength side where the reflectance is 60% or less and the wavelength on the longest wavelength side where the reflectance is 25% or less is 30 nm or less. . The film according to claim 1, wherein a difference between a maximum value and a minimum value of reflectance in a wavelength band of 400 to 700 nm measured at an incident angle of 60 ° is 15% or less. The film according to claim 1 or 2, wherein the color difference ΔE of the reflected color of the D65 light source before and after the durability test is performed under the following conditions is 7 or less.
<Durability test>
The reflective film is irradiated for 462 hours at an irradiance of 180 W / m ² using a xenon lamp (manufactured by Suga Test Instruments, SC750) under the conditions of a temperature of 95 ° C. and a relative humidity of 30% RH. It has a layer made of crystalline thermoplastic resin A (hereinafter referred to as A layer) and a thermoplastic resin B (hereinafter referred to as B layer) containing an amorphous resin, and the A layer and B layer are in the thickness direction. The film according to claim 1, wherein a total of 200 or more layers are alternately laminated. The film in any one of Claims 1-4 used for the reflecting material of a liquid crystal display. The film in any one of Claims 1-5 used for the reflecting material of a head-up display apparatus. A film formed by a coextrusion method, which has a layer made of a crystalline thermoplastic resin A (hereinafter referred to as A layer) and a thermoplastic resin B (hereinafter referred to as B layer) containing an amorphous resin. And the manufacturing method of the film in any one of Claims 1-6 by which the said A layer and B layer were laminated | stacked more than total 200 layers alternately by the thickness direction.