JP2007176154A - Laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film having an excellent lamination accuracy and optical performance without requiring the conventional complicated lamination method. <P>SOLUTION: A feed block which is a multilayered laminate of at least two or more kinds of resins comprises two or more slit boards. The film is manufactured by using the feed block which keeps the slit width in a slit board for forming a thick film layer positioned at both ends twice or more that for forming other thin film layers. The film is laminated in a thickness direction by 250 layers or more, at least three or more thick film layers having a thickness of ≥1 μm and ≤30 μm are contained, and in the laminated film, the maximum value of a reflectance in wavelengths of 250-2,600 nm is 60% or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a laminate that can selectively cut light of a specific wavelength by utilizing a light interference phenomenon that occurs by alternately laminating two types of resin layers having different refractive indexes at a layer thickness of light wavelength level. It relates to film.

  Conventionally, optical interference that selectively cuts light of a specific wavelength by utilizing the light interference phenomenon that occurs by alternately laminating two or more materials with different refractive indexes at the layer thickness of the light wavelength level. Multilayer films are known. Such multilayer films are already commercially available for various optical applications because optical filters with various performances can be achieved by setting the refractive index, number of layers, and thickness of each layer to the desired optical design. Has been. For example, a cold mirror, a half mirror, a laser mirror, a dichroic filter, a heat ray reflective film, a near-infrared cut filter, a monochromatic filter, a polarizing reflective film, and the like.

On the other hand, in recent years, an optical interference multilayer film formed by a melt film forming method of a thermoplastic resin is spreading in place of a conventional multilayer film formed by a vapor deposition method of an inorganic material. However, in the multilayer film formed by the melt film forming method, the refractive index difference between different materials is lower than the conventional one, and not only a large number of layers are required, but also the optical filter described above is achieved from the difference in the lamination method. In order to achieve this, it is necessary to realize a multilayer film structure with high stacking accuracy as in the optical design. Therefore, various methods for laminating thermoplastic resins have been studied. For example, supplying at least a first stream and a second stream of extrudable thermoplastic resin plasticized by heat, each of the first and second streams comprising a plurality of first and second substreams Splitting into streams; combining the first and second substreams to form a composite stream in which the first and second substreams are alternately arranged; and thermoplastic plasticized by heat Applying a third flow of resin to the outer surface of the composite flow to form a protective boundary layer, wherein the third flow of thermoplastic resin is the first or second flow of thermoplastic material. Mechanically manipulating the composite stream having a protective boundary layer, having a viscosity less than or equal to any of the two and being supplied at a flow rate of about 1 to 12.5% of the total amount of the composite stream; By shaping the operation flow And extruding the manipulated stream into a plurality of polymer objects having a plurality of substantially parallel layers of the first and second thermoplastic materials. A method has been proposed. (Patent Document 1) However, in this laminating method, the number of layers is increased by repeating the mechanical operation many times in the composite flow. Therefore, as the required number of layers increases, the destruction of the layers progresses and the high laminating accuracy The realization of was difficult. Further, after the thermoplastic resin A and the thermoplastic resin B are multi-layered by the pores in the multi-layer feed block, the branched thermoplastic resin A and the thermoplastic resin B alternately flow in 11 layers or more in parallel. There has been proposed a method for obtaining a multilayer film by guiding it to a flat flow path partitioned by a plate and further guiding it to a confluence in a multilayer feed block. However, in this laminating method, as the number of layers increases, the size of the device increases, so that it is difficult to laminate 200 layers or more, and the destruction of the layers also proceeds. (Patent Document 2) Further, for the purpose of improving handling properties, a multilayer film in which the outermost layer is thickened has been proposed. (Patent Document 3) However, the outermost layer similar to the protective layer of Patent Document 1 merges through the outermost layer flow path after the formation of the multilayer flow, and the problem of enlargement due to the increase in the number of layers substantially. Furthermore, the present situation is that the essential problem of layer destruction has not yet been solved.
Japanese translation of PCT publication No. 8-501994 (2nd page) JP 2003-112355 A (second page) Japanese Patent Laying-Open No. 2003-251675 (second term)

  An object of the present invention is to provide a laminated film excellent in lamination accuracy and excellent in optical performance without requiring a conventional complicated lamination method in view of the above-described problems of the prior art.

  In order to solve the above-mentioned problems, the laminated film of the present invention has a structure in which at least two kinds of resin blocks are laminated in a multilayer structure using two or more slit plates, which are positioned at both ends of the slit plate. It is a film manufactured using a feed block whose slit width forming a thick film layer is twice or more the slit width forming another thin film layer, and the film is laminated by 250 layers or more in the thickness direction, It is a laminated film having at least three thick film layers having a thickness of 1 μm or more and 30 μm or less and having a maximum reflectance of 60% or more at a wavelength of 250 to 2600 nm.

  The laminated film of the present invention provides a laminated film having high optical performance that realizes high lamination accuracy even when the number of layers increases and reflects or transmits light of a specific wavelength. In particular, in the case of a laminated film designed with a wide reflection band, even in the lamination between resins having different compositions, even in the spectral reflection spectrum, there is no wave drop (partial low reflection band), and the reflection is uniformly high. The laminated film which has a rate is provided.

Details of the present invention will be described below.
The resin used for the laminated film of the present invention may be any resin such as thermoplastic, thermosetting, and photocurable. In particular, the resin of the present invention is preferably a thermoplastic resin from the viewpoint of moldability and ease of handling.

  The manufacturing method of the laminated | multilayer film laminated | stacked on the multilayer of this invention can be illustrated as follows. For example, in the case of (AB) n · A laminated film, resin is supplied from two extruders A and B corresponding to the A layer, and the polymer from each channel is filtered. Furthermore, the melted product that passed through the gear pump that adjusts the discharge ratio, and was further laminated through the multi-manifold die, feed block, square mixer, and static mixer was melt-extruded into a sheet using a T-type die, and then cast. There is a method of cooling and solidifying on a drum to obtain an unstretched film.

  The laminated film of the present invention can be suitably obtained by using a feed block. In this case, the feed block for laminating at least two kinds of resins in multiple layers has a configuration using two or more slit plates. is required. FIG. 1 shows an example of a feed block which is an embodiment of 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. 1, member plates 1 to 9 are stacked in this order to form a feed block 10.

  The feed block 10 shown in FIG. 1 is derived from the resin introduction plates 2, 4, 6, and 8 and has four resin introduction ports. For example, the resin A is supplied from the introduction port 11 of the resin introduction plates 2 and 6, and the resin B is supplied from the introduction port 11 of the resin introduction plates 4 and 8. Then, the slit plate 3 receives the resin A from the resin introduction plate 2 and the resin B from the resin introduction plate 4, and the slit plate 5 receives the resin A from the resin introduction plate 6 and the resin B from the resin introduction plate 4. The receiving and slit plate 7 receives the supply of the resin A from the resin introduction plate 6 and the resin B from the resin introduction plate 8.

  Here, the type of resin introduced into each slit plate is determined by the positional relationship between the bottom surface of the liquid reservoir 12 in the resin introduction plates 2, 4, 6, and 8 and the end of each slit in the slit plate. That is, as shown in FIG. 3, the ridge line 13 at the top of each slit in the slit plate is inclined with respect to the thickness direction of the slit plate (FIGS. 2B and 2C). However, as shown in FIG. 2A, the slit width for forming the thick film layer positioned at both ends of the slit plate is the slit width for forming another thin film layer from the viewpoint of preventing the thin film layer from being destroyed. It is necessary to be at least twice the above. 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.

  As shown in FIG. 3, the height of the bottom surface of the liquid reservoir 12 in the resin introduction plates 2, 4, 6, 8 (8 is omitted from FIG. 3 because it is a repetitive structure) is the upper end of the ridge line 13. It is located at a height between the part 14 and the lower end part 15. Accordingly, resin is introduced from the liquid reservoir 12 of the resin introduction plates 2, 4, 6 and 8 from the side where the ridgeline 13 is raised (16 in FIG. 3), but from the side where the ridgeline 13 is lowered. Is in a state where the slit is sealed and no resin is introduced. Thus, since the resin A or B is selectively introduced for each slit, a flow of resin having a laminated structure is formed in the slit plates 3, 5, and 7 (7 is a repetitive structure and is omitted from FIG. 3). It flows out from the outlet 17 below the slit plates 3, 5, 7.

  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 Z-direction slit lengths in FIG. 1) is 20 mm or more. On the other hand, the width that is the gap of the slit is preferably 0.3 mm or more, more preferably 0.5 mm or more and 3 mm or less from the viewpoint of processing accuracy. Thus, the thickness of each layer can be controlled by adjusting the width and length of the slit. 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 part makes the flow velocity distribution in the width direction (Y direction in FIG. 1) 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.
More preferably, the resin is supplied from one liquid reservoir to two or more slit plates. In this way, even if the flow distribution is slightly generated in the width direction inside the slit plate, since it is further laminated in the confluence apparatus described below, the lamination ratio is made uniform in total, It is possible to reduce unevenness in the high-order reflection band.

  As shown in FIG. 1, the outlets 17 below the slit plates 3, 5, 7 are arranged in a positional relationship in which three resin flow laminated structures are arranged in parallel, and are separated from each other by the resin introduction plates 4, 6. ing. The shape of the outlet 17 preferably has an aspect ratio of 1 or more from the viewpoint of increasing the lamination accuracy. The aspect ratio here is the ratio of the length in the lamination direction (X-axis direction in FIG. 1) to the length in the film width direction (Y-axis direction in FIG. 1).

The laminated film of the present invention is preferably manufactured using a merging device 18 as shown in FIG. 4 (a) arranged immediately below the feed block 10 in FIG. 1 (Z direction). 4B, 4C, and 4D are XY cross-sectional views taken along lines LL ′, MM ′, and NN ′ in FIG. 4A, respectively. Hereinafter, three resin flows after the slit plate will be described. As can be understood from the cross-sectional views of FIGS. 4B and 4C from the middle LL ′ to the MM ′ by the merging device 18 shown in FIG. Conversion takes place and the three resin flow configurations change from parallel to serial. Here, the cross-sectional area of the resin flow path from LL ′ to MM ′ in FIG. 4A is preferably all constant from the viewpoint of increasing the lamination accuracy. Also, the area of the cross-sectional shape at the position MM ′ should be as wide as possible from the viewpoint of adjusting the flow rate of the polymer and controlling the stacking disorder. Specifically, the discharge amount of the alternately laminated resin that passes through the cross-sectional area within the unit time is preferably 40 kg / hr / cm ² or less. More preferably, it is 30 kg / hr / cm ² or less, and further preferably 20 kg / hr / cm ² or less. Further, the resin flow is widened from MM ′ to NN ′ in FIG. 4A, and flows into the base portion downstream from NN ′ in FIG.

  It is also preferable to arrange a square mixer as shown in FIG. 5 next to N-N 'in FIG. The XY cross section of Fig.5 (a) is shown to FIG.5 (b), (c), (d). By using a square mixer, the number of laminated layers can be easily increased. As a result, the spectral reflectance spectrum of the laminated film has a uniform high reflectance without wave breaks (partial low reflection band). It is because it can be made to achieve.

The square mixer is a polymer that has passed through a channel having a rectangular cross-sectional shape such as NN ′ in FIG. 4 once in a film width direction into a square channel as shown in FIG. It is a cylindrical body provided with a merging portion which is divided into two and is joined so that the branched polymer shown in FIG. 5 (c) is again laminated in the thickness direction as shown in FIG. 5 (d). is there. By connecting n such square mixers in series and repeatedly passing the molten polymer, it is possible to obtain a multi-layered laminate. For example, if the outermost layer in the thickness direction of the original laminate is the same resin and has K layers (K is an odd number), when passing through the square mixer n times, a laminate of (K-1) × 2 ⁿ +1 layers and Become. In the laminated body of the present invention, n is preferably 2 or less because the lamination accuracy deteriorates if it passes through the square mixer too much. More preferably, 1.

  Thereafter, the molten resin flow is filled in the manifold portion inside the T die, further widened, then extruded into a sheet form from the die slit, and solidified on a cooling roll below the glass transition temperature of the resin. A stretched laminated film is obtained. The laminated film which is an unstretched film thus obtained has high lamination accuracy.

  Furthermore, if necessary, a laminated film is obtained by a method of stretching the unstretched film at a temperature equal to or higher than the glass transition point (Tg) of the resin composition. The stretching method at this time is preferably stretched in at least one direction from the viewpoint of thermal dimensional stability. In particular, biaxial stretching is preferably performed by a known biaxial stretching method. The known biaxial stretching method may be a method of stretching in the width direction after stretching in the longitudinal direction, a method of stretching in the longitudinal direction after stretching in the width direction, and a plurality of stretching in the longitudinal direction and stretching in the width direction. You may carry out in combination. For example, in the case of a stretched film composed of polyester, the stretching temperature and the stretching ratio may be any amount, but in the case of a normal polyester film, the stretching temperature is 80 ° C. or more and 130 ° C. or less, and the stretching ratio is 2 times. It is preferably 7 times or more. More preferably, the stretching temperature is 90 ° C. or more and less than 110 ° C., and the stretching ratio is 3.4 times or more and 5 times or less from the viewpoint of reducing the thickness unevenness. The stretched film is then heat treated. This heat treatment is generally performed at a temperature higher than the stretching temperature and lower than the melting point. In the case of ordinary polyester, it is preferably performed in the range of 130 ° C. to 250 ° C., but more preferably in the range of 200 ° C. to 240 ° C. from the viewpoint of suppressing the heat shrinkage rate. Further, in order to impart thermal dimensional stability of the film, it is preferable to perform a relaxation heat treatment of about 2 to 10% at a temperature not lower than the glass transition temperature of the film and lower than 200 ° C. The laminated film of the present invention is achieved by the manufacturing process described above.

  Further, the laminated film of the present invention will be described in detail. The thickness of the laminated film of the present invention is determined from the balance between the thickness of each layer and the total number of laminated layers, but is preferably 20 μm to 300 μm from the viewpoint of ease of use. More preferably, it is 50 micrometers-200 micrometers.

  In addition, in the laminated film of the present invention, various additives such as antioxidants, heat stabilizers, lubricants, pigments, dyes, antistatic agents, fillers, nucleating agents, etc. do not deteriorate their properties. It may be added to. In particular, it is preferable to add an easy lubricant from the viewpoint of imparting slipperiness. As an easy lubricant, it can divide roughly into an organic and inorganic lubricant. As the shape, shape particles such as aggregated particles, spherical particles, beaded particles, complex particles, and scale-like particles can be used. In addition, the inorganic materials include silicon oxide, calcium carbonate, titanium oxide, alumina, zirconia, aluminum silicate, mica, clay, talc, barium sulfate, etc., and the organic materials include polyimide resin, olefin or Modified olefin resins, cross-linked or non-cross-linked polystyrene resins, cross-linked or non-cross-linked acrylic resins, fluororesins, silicone resins, and other organic lubricants such as stearamide, oleic amide, and fumaric amide Mention may be made of amide compounds. In particular, in the laminated film of the present invention, the primary average particle diameter of the particles is 0.6 μm or more and 3 μm or less, and the particle concentration is 0.02 to 0 from the viewpoint of imparting regular light reflectivity and slipperiness. 0.08% by weight is preferred. On the other hand, from the viewpoint of design properties, 0.1% by weight or more may be added in order to impart light diffuse reflection performance. As for the particle type, agglomerated silica is preferable from the viewpoint of cost and high reflectance. From the viewpoint of blocking heat rays, near-infrared absorbing particles that absorb light having a wavelength of 800 to 1200 nm may be added. As the near-infrared absorbing particles, for example, ATO (antimony tin oxide), ITO (indium tin oxide), diimonium salt or the like may be added as an auxiliary function.

  The laminated film of the present invention has 250 or more layers laminated in the thickness direction, contains 3 or more thick film layers having a thickness of at least 1 μm or more and 30 μm or less, and has a maximum reflectance of 60% at a wavelength of 250 to 2600 nm. It is necessary to be a laminated film as described above.

  In the laminated film of the present invention, it is important that at least 250 different resin layers are alternately laminated in the thickness direction in order to realize a very high reflectance. With such a laminated structure, the reflection wavelength and the reflectance can be controlled.

  The laminated structure of the present invention has a structure in which two types of resins are alternately laminated like A (BA) n from the viewpoint of manufacturing cost, simplicity in optical design, and further from the viewpoint of design of the feed block. Is preferably adopted. However, n is the number of repetitions and is a natural number. In particular, when the third type of resin C is used, a repeating structure of (ACB) n may be used, but from the viewpoint of difficulty in process, a laminated structure of CA (BA) nC or CA (BA) n. Is most preferable. The achievement method of these structures can be formed by using pinols installed from FIG. 4 (a) after M-M ′ to the base. That is, it can be achieved by the resin C supplied from the third extruder being joined to the A (BA) n multilayer flow by pinol.

The control of the reflectivity by the laminated structure uses the principle of interference reflection. Interference reflection is a phenomenon in which a large number of thin layers having different media, that is, different refractive indexes are stacked, and reflected lights on the boundary surface interfere with each other and strengthen each other. For example, for a multilayer film in which a large number of two types of resins A and B are alternately stacked, when light is incident perpendicularly to the film surface, light having a wavelength λ (nm) satisfying the following condition is generated at the interface of the stack. reflect.
2 · (nA · dA + nB · dB) = nλ (5)
here,
nA: Refractive index of resin A nB: Refractive index of resin B dA (nm): Layer thickness of resin A dB (nm): Layer thickness of resin B n: Natural number representing the order of reflection. Accordingly, the reflection wavelength λ can be arbitrarily set by selecting the resins A and B and adjusting the layer thickness.

  When the resin C is employed, auxiliary functions that play a role other than the optical interference phenomenon expressed by the resins A and B are required. Therefore, the resin used, the refractive index, the thickness, and the like depend on the auxiliary functions. What is necessary is just to determine suitably. Examples of the auxiliary function include light absorption, light diffuse reflection performance and slipperiness, and adjustment of surface free energy (given easy adhesion). For example, in the structure of CA (BA) n, when the resin C containing black such as carbon black is used, interference reflection color stands out when observed from the surface where the resin C is not provided. In the structure of CA (BA) nC, light resistance is imparted when the resin C is a material that absorbs ultraviolet rays. Furthermore, if the particles are added to the resin C at a high concentration, diffuse reflection performance and slipperiness are imparted. Further, depending on the composition of the resin C, the surface free energy is also adjusted. Therefore, the layer thickness of the resin C may be appropriately determined and adjusted according to the purpose, but is preferably 0.1 μm or more and 10 μm or less from the viewpoint of an auxiliary function. In particular, as the resin C, various additives are contained, and it is most preferable that the matrix resin is either the resin A or the resin B. Moreover, it is preferable that it is a matrix resin which shares the same component as the composition of resin A or resin B. Sharing the same component means containing the same basic skeleton. The basic skeleton is a repeating unit constituting the resin. For example, when one resin is polyethylene terephthalate, ethylene terephthalate is the basic skeleton. As another example, when one resin is polyethylene, ethylene is a basic skeleton. It is preferable that the resin A and the resin B are resins containing the same basic skeleton because the layer is hardly broken. The laminated structure of the laminated film of the present invention is determined according to the performance of the target optical filter. For example, in the case of a narrow-band reflective film that has a function of reflecting only light of a specific wavelength and transmitting other light, a periodic structure in which the layer thickness of the resin A and the layer thickness of the resin B are constant. In the case of a broadband reflective film having a function of transmitting or reflecting all light of a certain wavelength or more, the resin A layer thickness and the resin B layer thickness change at a constant rate. It is necessary to form an inclined structure.

  Specifically, the wavelengths λ and λ ′ that are the ends of the desired reflection wavelength band are determined, and the design layer thickness corresponding to the reflection wavelength λ according to the above formula (5) from the lamination ratio and refractive index of the known thin film layer Further, dA and dB are respectively obtained as layer thicknesses dA ′ and dB ′ corresponding to the reflection wavelength λ ′ which is the end of the other opposite band. The layer thickness between dA → dA ′ and between dB → dB ′ is such that the layer thickness distribution changes continuously or discretely with monotonic increase or monotonic decrease. However, the lamination ratio here is a value obtained from the ratio of the discharge amount of the resin B to the resin A in consideration of the thick film layer whose magnification with respect to the thin film layer is known. If the target function of any optical performance is determined, the optimal structure can be determined by optical calculation. For the theory of optical calculation, see H.H. A. McLeod (translated by Shigetaro Ogura) “Optical Thin Film” (Nikkan Kogyo Shimbun) (1989), Mitsunobu Koisoyama “Basic Theory of Optical Thin Film” (Opttronics) (2003).

  A method of controlling the distribution of the layer thickness is to adjust all the widths and lengths of the slits of the slit plates of the feed block. It is understood from the fact that the polymer passing through the slit is generally represented by the following formula (6).

Where, Q: Resin flow rate t: Slit width W: Slit depth μ: Resin viscosity L: Slit length ΔP: Pressure drop That is, if the pressure in the liquid reservoir is made uniform and the pressure drop ΔP is constant When considered, the flow rate Q corresponding to the layer thickness of one layer can be easily adjusted by adjusting one slit size. However, since all slit size designs only determine the flow balance between the layers, the final layer thickness distribution is determined by the thickness of the laminated film.

  Moreover, when using a square mixer, two or more reflecting the layer thickness distribution formed by the feed block are formed. For example, if the resin distribution ratio (area ratio of 23O and 24O flow paths) in the OO ′ cross section shown in FIG. 5 is the same, two similar layer thickness distributions indicate the thickness direction in the laminated film. Will be formed side by side. In addition, by changing the distribution ratio, two layer thickness distributions having different thicknesses proportional to the value can be obtained. That is, a laminated film in which two similar layer thickness distributions having different thicknesses are arranged in the thickness direction is obtained. In the laminated film of the present invention, when the layer thickness distribution in the feed block is a periodic structure, the distribution ratio is preferably 1: 1, and in the case of the inclined structure, about 1: 1 to 1: 0.8 is uniformly high. It is preferable from the viewpoint of achieving the reflectance. This is because if the difference in distribution ratio is large, a partial low reflection band called wave drop is likely to occur.

  In particular, the laminated film of the present invention requires a lamination number of 250 layers or more from the viewpoint of being suitable for a broadband reflective film that realizes a uniform high reflectance over a wide wavelength band in the lamination process, Is 500 layers or more, more preferably 800 layers or more. More preferably, it is 1500 layers or more. The method of increasing the number of layers can be achieved by increasing the number of slit plates and slits. Usually, the maximum number of slits in one slit plate is about 300 from the viewpoint of achieving high stacking accuracy, and the number of slit plates is also about 5 from the viewpoint of increasing the size of the stacking apparatus. is there. Or it can achieve by using a square mixer together with a feed block. By going through such a lamination process, a laminate of 1000 layers or more can be easily obtained at a time.

The laminated film of the present invention may be produced by solution casting or melt casting. In particular, in the present invention, it is preferable to use melt film formation from the viewpoint of easy handling of production equipment and resin.
Furthermore, the laminated film of the present invention can also be achieved by laminating laminated films formed by melt film formation having different thicknesses via an adhesive. If the number of bonded sheets is large, the laminated film may curl after bonding due to the difference in thickness. Therefore, the number of laminated sheets is preferably 3 or less, and more preferably 2 sheets are bonded from the viewpoint of symmetry. The adhesive used for laminating the laminated films may be any of heat, UV curable acrylic, urethane, and polyester. As the coating method, for example, a reverse coating method, a gravure coating method, a rod coating method, a barcode method, a Mayer barcode method, a die coating method, a spray coating, or the like can be used.

  In addition, the laminated film of the present invention needs to include at least 3 thick film layers having a thickness of 1 μm or more and 30 μm or less. If the thickness is less than 1 μm, the thin film layer in the vicinity of the thick film layer tends to be thinner than the design layer thickness in the lamination process. On the other hand, if the thickness exceeds 30 μm, the thick film layer alone results in a film having a thickness of at least 90 μm or more. Therefore, it is more preferably 1 μm or more and 10 μm or less. Furthermore, it is preferably 1 μm or more and 5 μm or less. The thickness of the thick film layer is achieved by adjusting the slit width and the slit length (length in the Z-axis direction in FIG. 2) for forming the thick film layer located at both ends of the slit plate. Can do. For example, the width of the slit for forming the thick film layer of the present invention is preferably 1 mm or more and less than 5 mm, and the width of the slit for forming the thin film layer is preferably 0.5 mm or more and 3 mm or less. Moreover, since it is difficult to control layer thickness distribution when there are too many layers of a thick film layer, it is preferable that it is 15 layers or less. More preferably, it is 10 layers or less.

  The laminated film of the present invention needs to have a maximum reflectance of 60% or more at a wavelength of 250 to 2600 nm. If the maximum reflectance is less than 60%, it may not be used as an optical filter or the like. The maximum value of the reflectance is preferably 80% or more, and more preferably 100% or more. As a method for achieving this, it is preferable that the resin is selected, and further that the in-plane refractive index difference between the resins A and B is 0.05 or more, more preferably 0.08 or more. More preferably, it is 0.1 or more. The in-plane refractive index is the MD of a film in the case where a single film composed only of one of the resins is formed under the same film forming conditions as the laminated film obtained by alternately laminating resins A and B. It means the average value of the refractive index in the (Machine Direction) direction and the refractive index in the TD (Transverse Direction) direction.

  That is, the in-plane refractive index difference is a difference in in-plane refractive index between both films formed of one resin. The in-plane refractive index can be measured using a known Abbe refractometer. For example, in the case of a polyethylene terephthalate film oriented and crystallized by known biaxial stretching and heat treatment, the in-plane refractive index is about 1.6 to 1.67. In addition, the copolymerized polyethylene terephthalate stretched and heat-treated under the same conditions as the above-mentioned polyethylene terephthalate is usually amorphous or melts because the heat treatment temperature is a melting point lower than that of polyethylene terephthalate, resulting in orientation relaxation and its surface. The internal refractive index is about 1.52 to 1.59. That is, in this case, the in-plane refractive index difference can be adjusted to 0.05 to 0.12 by variously examining the film forming conditions. In particular, a combination of a resin of polyethylene terephthalate and a copolymer thereof is preferable because the compatibility between the resins is good and a flow mark that causes a quality problem of the laminated film hardly occurs.

  In addition, the laminated film of the present invention preferably has a reflectance of 60% or more continuously over a wavelength section of 150 nm from the viewpoint of application to a film having a metallic appearance or a near-infrared shielding film. More preferably, it has a reflection band of 75% or more, and more preferably 90% or more. Furthermore, it is more preferable that the continuous wavelength section which is a reflection band having a reflectance of 60% or more is 200 nm or more.

  The laminated film formed by melting according to the present invention is preferably a film obtained by a T-die method. That is, a process in which the resin melted, kneaded and measured by the extruder is uniformly pressure-dropped to the entire width of the die lip by the T die to uniformize the film thickness and then forcibly cooled and solidified on the cooling roll is obtained. It is a laminated film formed. Next, a stretching / heat treatment step may be included.

  The laminated film of the present invention has a thick film layer at least as the outermost layer, and at least 50 thin film layers having a layer thickness of 0.01 to 0.4 μm between adjacent thick film layers in the permutation of the thick film layers It is preferably included.

  By forming a thick film layer at least on the outermost layer of the laminated film of the present invention, not only the thin film layer in the vicinity is suppressed in the lamination process, but also delamination of the surface layer portion of the laminated film of the present invention is suppressed. To act as a protective layer. The cause of this thinning can be discussed in general fluid theory. That is, the resin flow that becomes the outermost layer portion is likely to be subjected to flow resistance because it flows along the wall surface portion of the flow path in the manufacturing process. Similarly, since the layers that become adjacent thin film layers are close to the wall surface, the flow rate is reduced due to flow resistance, and the layer thickness is reduced as a result of each layer. However, by increasing the flow rate of the resin flow that flows in the outermost layer, the resin flow in the layer that becomes the thin film layer becomes less susceptible to flow resistance as it gets farther from the wall surface, and thinning can be prevented. From the viewpoint of preventing this thinning, it is more preferable that the outermost layer on the front and back side has a thick film layer of 1 μm or more and 10 μm or less. Moreover, although the layer thickness of the thin film layer located between a thick film layer is good to set according to the refractive index of resin which comprises each layer, the refractive index of resin is about 1.35-1 normally. In this case, the thickness of each layer is such that the thickness of the thin film layer is 0.01 μm or more and 0.4 μm or less from the viewpoint of causing an optical interference phenomenon with respect to light wavelengths from the near ultraviolet to the infrared region. Preferably there is. More preferably, they are 0.05 micrometer or more and 0.3 micrometer or less.

  Furthermore, it is preferable that 50 or more thin film layers are included between adjacent thick film layers in the permutation of the thick film layers. Usually, if there is no thick film layer, the number of thin film layers that can be made thinner is about 50 layers depending on the resistance of the inner wall of the polymer flow path. From the viewpoint of effectively utilizing the thickest film layer, it is preferable that 50 or more thin film layers are included. More preferably, it is 100 layers or more. The permutation of thick film layers refers to the arrangement of thick film layers when attention is paid only to thick film layers having a thickness of 1 μm or more among all the layers of the laminated film of the present invention.

  As a means for achieving the above laminated structure, the number of layers is adjusted by adjusting the number of slits in the feed block, and the layer thickness by adjusting the slit length, depth, and width (layer thickness). Thickness distribution) is determined, and the individual layer thickness is determined by adjusting the thickness of the laminated film. The thickness of the laminated film can be adjusted by the peripheral speed of a cooling roll such as a casting drum or the discharge amount of an extruder.

In the distribution of the layer number and the layer thickness in the thin film layer of at least one kind of resin constituting the laminated film of the present invention, the layer thickness average for 30 layers from one outermost layer side is E1 (nm), and the other outermost layer side When the average layer thickness for 30 layers is E2 (nm) and the average layer thickness for 30 layers in the center in the thickness direction is C (nm), the following formulas (1) and (2) are satisfied simultaneously. It is preferable.
E1 ≧ C ≧ E2 (1)
0.9 ≧ E2 / E1 ≧ 0.3 Expression (2).

  The layer number is a value assigned a number for each layer of the laminated film of the present invention. That is, if one outermost layer is 1, the other outermost layer is the number of the total number of layers. However, the term “one layer” here refers to a layer sandwiched between a boundary line formed between different media and another adjacent boundary line as one layer. For example, two layers laminated in a state where two resin layers having the same composition are arranged adjacent to each other are regarded as one layer. More specifically, for example, when a thick film layer of resin A, a thin film layer of resin A, a thin film layer of resin B, a thin film layer of resin A,... The number 1 is the sum of the thick film layer and the thin film layer of the resin A is the thick film layer, then the layer number 2 is the thin film layer of the resin B, and the layer number 3 is defined as the thin film layer of the resin A . When the laminated film of the present invention is composed of two types of resins, this definition is repeated, so that the type of resin is always determined by the odd or even layer number. However, when the resin C is used, the first or / and last layer number is assigned to the layer number.

  The layer thickness distribution of the thin film layer is obtained by observing a cross section in the thickness direction of the laminated film at a magnification of about 40,000 times using a transmission electron microscope (TEM), thereby obtaining the layer thickness for each layer number. On the other hand, the thickness of a thick film layer of 5 μm or more can be obtained by observing a cross section at about 10,000 times with a TEM or by observing a cross section at about 5000 times using a scanning electron microscope (SEM).

  About 30 layers in the central portion in the thickness direction of the laminated film of the present invention means that the same kind of resin layers continuously arranged around the middle point of the total number of thin film layers are arranged in the thickness direction up and down, respectively. , 14 or 15 layers. For example, if the total number N of thin film layers is an odd number, the layer corresponding to the middle point is the (N + 1) / 2th layer, which corresponds to the odd number of layers in the thickness direction (N + 1) / 2-30. (N + 1) / 2-2, (N + 1) / 2, (N + 1) / 2 + 2,... (N + 1) / 2 + 28 corresponds to 30 layers in the central portion in the thickness direction. In addition, if the laminated film of the present invention is obtained by alternately laminating two kinds of resins in the thickness direction, the type of the resin layer is distinguished depending on whether the layer number is an odd number or an even number. Similarly, if the total number N of thin film layers is an even number, the layer corresponding to the middle point is the N / 2th, and the upper and lower sides in the thickness direction are N / 2-30... N / 2-2, N, respectively. The layer number corresponding to / 2, N / 2 + 2,... N / 2 + 28 corresponds to 30 layers in the central portion in the thickness direction. And let the average of these layer thickness be C (nm). The same method can be used for E1 and E2. However, it is preferable that Formula (1) and Formula (2) hold simultaneously when focusing on at least one type of resin layer. More preferably, the two types of resin layers are preferably formed simultaneously. Moreover, it can obtain | require similarly also with the laminated | multilayer film obtained using the square mixer. When an inclined structure and a non-equally distributed square mixer are used, it is assumed that the layer thickness distribution of the thin film layer where the layer thickness is the thickest in design is arranged on the outermost layer side of the laminated film. The layer thickness distribution of the thin film layer that is the thickest in design is a layer thickness distribution that is designed so that the average layer thickness of the thin film layer sandwiched between the thick film layers is the largest.

  In the laminated film of the present invention, E2 / E1 is more preferably 0.4 or more and 0.8 or less in the formula (2) from the viewpoint of reducing partial wave loss. Such an inclined structure can be achieved by making the slit width and depth constant and changing only the slit length continuously. Moreover, it can achieve by setting the value of the shortest slit length / longest slit length, which is the ratio of the change in the slit length, to be in the range of 0.4 to 0.7. Here, the partial wave drop (low reflection band) in the spectral reflection spectrum will be described. The laminated film having an inclined structure according to the present invention is optically designed to have a spectral spectrum having a rectangular wave shape of one mountain (the ridge portion is a high reflection band) in the spectral reflection spectrum. For this reason, the presence of a low reflectance region in a mountain or the presence of a small reflection peak next to a mountain degrades the optical performance in terms of quality. In the present invention, the portion of the low reflection band that deteriorates the optical performance is referred to as partial wave omission. Specifically, FIG. 7 shows a spectral reflection spectrum of a broadband reflection film without wave omission and FIG. 8 shows a spectral reflection spectrum of a broadband reflection film with severe wave omission. In FIG. 7, obviously, the reflectance is continuously distributed as 100% at a wavelength of 450 to 600 nm, whereas in FIG. 8, the reflectance shown by 34 in the figure is 60%. It can be seen that there is a partial low reflection region that is less than that and the optical performance is low.

  The laminated structure that simultaneously satisfies the above formulas (1) and (2) has a feed block configuration using a slit plate in which the length of the slit forming the thin film layer is monotonously increased or monotonously decreased, Furthermore, it is achieved by selecting an optimal combination of two types of resins having good compatibility and similar rheological properties. In addition, the slit plate in the feed block must be designed so that the slit width for forming the thick film layers located at both ends is at least twice the slit width for forming the other thin film layers. Yes, it is also important to optimize the shape of the slit and the shape of the polymer flow path in the short tube through which the polymer immediately after exiting the feed block passes. Here, the optimal combination of two kinds of resins is preferably a resin sharing the same kind of components. For example, polyesters, specifically, polyethylene terephthalate and copolymers thereof. Moreover, optimizing the slit shape means, for example, inclining as shown by 13 in FIG. Furthermore, optimization of the polymer flow path means, for example, increasing the distance of the polymer flow path between LL ′ and MM ′ in FIG. 4, increasing the aspect ratio of the cross-sectional shape, Or make it wider.

Furthermore, the laminated film of the present invention is provided on the thick film layer side in the thin film layer region sandwiching the thick film layer from the viewpoint of realizing high lamination accuracy and reducing partial wave omission (low reflection band) in the spectral reflection spectrum. The average thickness of each of the 10 thin film layers from the top to the bottom in the thickness direction is set to D1 (nm) and D2 (nm), and similarly, the next thick film layer from the thick film layer side to the top and bottom in the thickness direction. When the average layer thickness of the thin film layers is R1 (nm) and R2 (nm), respectively, it is preferable that the laminated structure satisfies the following expressions (3) and (4) at the same time.
R1 ≧ R2 Formula (3)
D1 ≦ D2 (Formula 4)
In the laminated film of the present invention, in the layer thickness distribution in the same resin, it is preferable that at least one laminated portion having a laminated structure satisfying the above two formulas simultaneously exists. Since the portion also depends on the number of thick film layers, for example, in a laminated film having two thick film layers as the outermost layer and two thick film layers inside, for example, a total of four thick film layers The number of laminated parts that simultaneously satisfy the above two formulas is two at the maximum. Considering resin A and resin B, which are different resins, there are four locations at the maximum. Therefore, the optimal aspect in this case is more preferably two or more.
One embodiment of the above-described stacked structure is illustrated with reference to FIG. FIG. 6 shows an example of the relationship between the layer number and the layer thickness (nm) when the resin A and the resin B are alternately laminated. It is assumed that the distribution is formed by a feed block composed of three slit plates. In FIG. 6, the layer thickness distribution of resin A and the layer thickness distribution of resin B are shown. The layer thickness distribution of the resin A is located above the layer thickness distribution of the resin B, and is configured by layer thickness distributions of 28, 29, 32, and 33 as shown in detail in FIG. Regarding the resin A, the thin film layer region sandwiching the thick film layer 29 is a thin film from the layer number of the thick film layer 29 indicated by the solid line in ascending order and descending order until reaching the next thick film layer 29. This is the distribution of the layers, here 32 and 33. The average layer thickness of the layer thickness distribution 32 of the thin film layer is R1 (nm), and the average layer thickness of the layer thickness distribution 33 is R2 (nm). Also, in each layer thickness distribution, out of the layer numbers counted from the thick film layer 29 in ascending order and descending order, the thin film layers of 10 layers close to the layer number of the thick film layer 29, and the average layer thickness of each of the thin film layers is D1. (Nm) and D2 (nm). In FIG. 6, ten thin film layers whose permutations are close to the layer number of the second thick film layer 29 correspond to 31 and 30, respectively.

  The laminated structure satisfying the expressions (3) and (4) is achieved by adjusting the distribution of the slit lengths of the slit plates. For example, a method for achieving the structure as shown in FIG. 6 will be described. In this case, the slit plate has a configuration of three sheets, and the slit length of each slit plate has a monotonically increasing slit length distribution, and between adjacent slit plates (here, 25 and 26) Designed so that the length and width distribution of at least 10 layers of slits arranged at the front and back are the same in the front and the back, with the slit forming the thick film layer serving as the joint of the layers as the center. Is achieved. The ratio of the change of the slit length of each slit plate can be achieved by adjusting to 0.9 to 0.5.

  As the resin forming the laminated structure in the present invention, polyethylene, polypropylene, polylactic acid, poly (4-methylpentene-1), polyvinylidene fluoride, cyclic polyolefin, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, nylon 6 11, 12, 66, and the like, polystyrene, polycarbonate, polyester, polyphenylene sulfide, polyether imide, and the like can be used. These may be homopolymers or copolymerized polymers. The two or more resins used in the present invention may be those using these resins, and may be a combination of a homopolymer and a copolymer, in which the copolymer ratio is changed in the same type of polymer.

  Of the above resins, cyclic polyolefin, poly (4-methylpentene-1), polycarbonate, polyester, polymethyl methacrylate, polystyrene and the like are preferable in terms of transparency and the like, from the viewpoint of heat resistance, dimensional stability, and cost. Polyester having high versatility is particularly preferable.

  The polyester is obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid or aliphatic dicarboxylic acid and a diol.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid and the like can be mentioned. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like. Of these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred. Only one acid component may be used alone, or two or more acid components may be used in combination. Furthermore, oxyacids 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, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4-hydroxy And ethoxyphenyl) propane. Among these, ethylene glycol can be preferably used. A diol component may be used individually by 1 type and may use 2 or more types together.

  In particular, polyesters include polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, and polyhexamethylene terephthalate and its copolymer. Examples thereof include a polymer, polyhexamethylene naphthalate and a copolymer thereof, and polyethylene terephthalate and a copolymer thereof are particularly preferable.

  Moreover, as a combination of at least two kinds of resins, from the viewpoint of achieving high reflectance, the resin A includes a layer comprising polyethylene terephthalate and the resin B includes cyclohexanedimethanol, spiroglycol, adipic acid, sebacic acid, It is preferably composed of a layer comprising a polyester obtained by copolymerizing isophthalic acid, cyclohexanedicarboxylic acid, diphenyldicarboxylic acid, naphthalenedicarboxylic acid, or the like. The copolymerization amount in the resin B is preferably 5 to 50 mol%. In the present invention, it is most preferable to use a polyester obtained by copolymerizing spiroglycol and cyclohexanedicarboxylic acid, particularly from the viewpoint of excellent optical performance. In that case, an ethylene terephthalate polycondensate having a copolymerization amount of spiroglycol and cyclohexanedicarboxylic acid of 5 to 30 mol% is most preferred. The resin B may be an alloy of polyethylene terephthalate and copolymer polyester.

  Further, from the viewpoint of achieving the laminated structure of the present invention, it is preferable that the solution viscosity of the resin, which is also an indicator of rheological properties, is low. Specifically, the intrinsic viscosity (IV: Intrinsic Viscosity) measured in orthochlorophenol is preferably 0.65 or less. More preferably, it is 0.56 or less.

Hereinafter, it demonstrates using the Example of the laminated | multilayer film of this invention.
[Methods for measuring physical properties and methods for evaluating effects]
The characteristic value evaluation method and the effect evaluation method are as follows.

(1) Lamination thickness, the number of laminations, and lamination structure The layer structure of the film was obtained by observing an electron microscope with respect to a sample obtained by cutting a cross section using a microtome. That is, using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), the cross section of the film was magnified 40000 times at an acceleration voltage of 75 kV, a cross-sectional photograph was taken, and the layer configuration and each layer thickness were measured. In some cases, in order to obtain high contrast, a staining technique using a known RuO ₄ or OsO ₄ may be used.

A specific method for obtaining the laminated structure will be described. About 40,000 times as many TEM photographic images were captured with CanonScan D123U at an image size of 720 dpi. The image is saved in the JPEG format, and then image processing software Image-Pro Plus ver. 4 (sales company Planetron Co., Ltd.) was used to open this JPG file and perform image analysis. In the image analysis process, the relationship between the thickness in the thickness direction and the average brightness of the area sandwiched between the two lines in the width direction was read as numerical data in the vertical thick profile mode. Using the spreadsheet software (Excel2000), the position (nm) and brightness data were subjected to numerical processing of sampling step 6 (decimation 6) and 3-point moving average. Furthermore, the data obtained by periodically changing the brightness is differentiated, and the maximum value and the minimum value of the differential curve are read by the VBA program. Calculated. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated. The laminated films of Examples 1 to 12 and Comparative Example 1 were all composed of a thin film layer of 0.01 μm to 0.4 μm and a thick film layer of 1 μm to 30 μm. The comparative example 2 was comprised only by the thin film layer, and the comparative example 3 was comprised by the layer of the thickness more than a thin film layer, a thick film layer, and a thick film layer.
In the distribution of the layer number and the layer thickness in the thin film layer of the resin, which is a copolymer of the obtained polyethylene terephthalate, the layer thickness average for 30 layers from one outermost layer side is E1 (nm), from the other outermost layer side The layer thickness average for 30 layers was E2 (nm), and the layer thickness average for 30 layers in the central portion in the thickness direction was C (nm). However, in the case of the inclined structure, the outermost layer that has been designed so that the layer thickness distribution is thinned in advance is the layer number 1, and the layer number is assigned to the reverse outermost layer in order, and the layer number 30 is smaller. The layer thickness average of the thin film layers for each layer was E1 (nm).

  In addition, in the thin film layer region of the resin layer that is a polyethylene terephthalate copolymer sandwiching the thick film layer that is polyethylene terephthalate, the thin film layers for 10 layers from the thick film layer side in the thickness direction up and down, the average layer of each Similarly, the thicknesses are D1 (nm) and D2 (nm). Similarly, the average thicknesses of the thin film layers from the thick film layer side to the next thick film layer in the thickness direction up and down are respectively R1 (nm) and R2 ( nm). When two or more D1, D2, R1, and R2 existed, the highest average value was adopted. However, in the case of the inclined structure, the layer thickness average of the thin film layers corresponding to the layer number 10 having a large number was D1 (nm).

(2) Maximum reflectance A spectrophotometer (U-3410 Spectrophotometer) manufactured by Hitachi Ltd. was fitted with a φ60 integrating sphere 130-0632 (Hitachi Ltd.) and a 10 ° inclined spacer, and the reflectance was measured. The bandpass is set to 2 nm / servo, the gain is set to 3, and the range from 250 nm to 2600 nm is set to 120 nm / min. The scanning speed was measured. In order to standardize the reflectivity, an aluminum oxide plate attached to the device is used as a standard reflector. When measuring samples, black paint is applied with “Magic Ink” (registered trademark) to eliminate interference caused by reflection from the back surface. did. The maximum value of the reflectance is the maximum value of the spectral reflectance at a wavelength of 250 to 2600 nm, and the wavelength is taken as the reflection wavelength.

(3) In-plane refractive index difference between different resins A single film was formed under the same film forming conditions as the laminated film, using the resin constituting the laminated film alone. In this case, the unstretched film was formed by the same method up to casting. Next, a sample is cut out from the unstretched film to a size of 10 cm × 10 cm, stretched using a biaxial stretching apparatus (Toyo Seiki Co., Ltd.), and the obtained stretched film is attached to a 20 cm × 20 cm metal frame. Then, heat treatment was performed using a tunnel oven (manufactured by Taishin Manufacturing Co., Ltd.) to obtain a single film. In addition, when the heat treatment temperature at the time of film formation was a temperature at which the resin was melted, it was sandwiched by a support such as a polyimide film and subjected to heat treatment in a tunnel oven. A sample was cut out from the center of the obtained single film in the width direction of the film in a dimension of 4 × length 3.5 cm, and the refractive index of MD and TD was measured using an Abbe refractometer 4T (manufactured by Atago Co., Ltd.). Asked. As a light source, a sodium D line wavelength of 589 nm was used. The average refractive index of MD and TD was defined as the in-plane refractive index, and the difference in in-plane refractive index between different resins was determined as the in-plane refractive index difference (absolute value) (| in-plane refractive index of resin A− In-plane refractive index of resin B |). As the immersion liquid, methylene iodide and a test piece having a refractive index of 1.74 were used.

(4) Solution viscosity (IV)
It calculated from the solution viscosity measured at 25 degreeC in orthochlorophenol. The solution viscosity was measured using an Ostwald viscometer. The unit is [dl / g]. The n number was 3, and the average value was adopted.
(5) Reflection performance evaluation In the spectral reflectance of the wavelength 250 nm to 2600 nm of (2) above, a spectral reflectance spectrum having a reflectance of 90% or more continuously over at least an arbitrary wavelength interval width of 150 nm, The evaluation was evaluated as ○ when 75% or more but less than 90%, Δ when 60% or more and less than 75%, and × when less than 60%.

However, with respect to Example 8 and Comparative Example 2, since the slit plate is designed so that the lengths of the slits forming the thin film layer are all the same, a narrow-band reflective film having a periodic structure is basically obtained. For this reason, the evaluation was made with a circle having a reflection wavelength bandwidth of 200 nm or less at a reflectance of 30% and a circle having a reflection wavelength bandwidth of 200 nm or less. Here, the reflection wavelength bandwidth at a reflectance of 30% is the wavelength λ1 (nm) and the wavelength λ2 (nm) corresponding to the intersection with the reflectance of 30% in the spectral reflection spectrum obtained by the measurement of (2) above. Difference (absolute value). In addition, the thing with 3 or more intersections was set as x.
[Example 1]
Polyethylene terephthalate with IV = 0.63 was used as Resin A (0.06 wt% of agglomerated silica having an average particle size of 1.2 μm was added to Resin A), and polyethylene with IV = 0.55 was used as Resin B. A terephthalate copolymer (polyethylene terephthalate copolymerized with 15 mol% of spiroglycol component and 20 mol% of cyclohexanedicarboxylic acid component) was used. (Resin B is particle-free). Resins A and B were melted at 280 ° C. in respective extruders, passed through five FSS type leaf disk filters, and the discharge ratio was resin A composition / resin B composition = 1.2 by a gear pump. / 1 and 269 slits with a number of slits of 267, and two 269 slit plates, a total of three, using a 801-layer feed block. It was set as the laminated body by which 801 layers were laminated | stacked alternately. However, in each slit plate used, the slit width for forming the thick film layer located at both ends is designed to be 2.8 times the slit width for forming the other thin film layer, and the slit width for forming the thin film layer is The relationship between the layer number and the slit length was designed to be similar to the layer thickness distribution of FIG. Here, the slit widths were all constant and only the length was changed. In addition, the rate of change of the slit length was 0.59. The breakdown of the laminated structure is a laminated body having an inclined structure in which resin A is 401 layers and resin B is 400 layers alternately laminated in the thickness direction.

Next, the cross-sectional shape of the polymer flow path through which the 801-layer laminated flow in which the laminated flow from each slit plate merges from the feed block passes through the polymer tube (the position of MM ′ in FIG. 4A) ) Used was a square shape with an aspect ratio (length in the width direction / length in the thickness direction) of 1.5. Moreover, the discharge amount of 801 layers of resin that passed through the cross-sectional area of the polymer tube within a unit time was 30 kg / hr / cm ² . The laminate was supplied to a T-die and formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic applied voltage of 8 kV with a wire to obtain an unstretched film. .

This unstretched film is longitudinally stretched at 100 ° C. and a stretching ratio of 3.5 times, led to a tenter that holds both ends with clips, 105 ° C. and 4.3 times transverse stretched, and then heat treated at 230 ° C., TD relaxation of about 5% was performed at 120 ° C. to obtain a laminated film having a thickness of 67 μm. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 1.5 μm, the layer thickness of layer number 267 is 3.1 μm, the layer thickness of layer number 535 is 3.4 μm, and the layer thickness of layer number 801 that is the outermost layer Was 1.7 μm, and these four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 30 nm to 115 nm, and an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. The obtained spectral reflection spectrum was confirmed to have a shape similar to FIG. It was a laminated film with a metallic luster that had a wavelength of 400 nm to 600 nm, had few wave breaks (partial low reflection band), and uniformly high reflectivity (75% or more). However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.11.
[Example 2]
Resin A of Example 1 was replaced with polyethylene naphthalate with IV = 0.67, and resin B was replaced with a copolymer of polyethylene naphthalate with IV = 0.62 (polyethylene naphthalate copolymerized with 20 mol% of terephthalic acid component). Furthermore, the cross-sectional area of the polymer flow path is enlarged, and the discharge amount of the 801 layers laminated resin passing through the cross-sectional area within a unit time is 10 kg / hr / cm ² , and the obtained unstretched film is Longitudinal stretching is performed at 135 ° C and a stretching ratio of 3.3 times, and both ends are guided to a tenter gripped by clips, and after 145 ° C and 4.1 times transverse stretching, heat treatment is performed at 240 ° C and about 5% at 150 ° C. A laminated film having a thickness of 69 μm was obtained in the same manner as in Example 1 except that the TD relaxation was performed. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 1.6 μm, the layer thickness of layer number 267 is 2.7 μm, the layer thickness of layer number 535 is 3.1 μm, and the layer thickness of layer number 801 that is the outermost layer Was 1.7 μm, and these four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 44 nm to 120 nm, and an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it was a laminated film with a metallic luster feeling that has a wavelength of 500 nm to 650 nm, has few wave breaks (partial low reflection band), and uniformly has a high reflectance. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.11.
[Example 3]
Resin B of Example 1 was replaced with a polyethylene terephthalate copolymer of IV = 0.82 (polyethylene terephthalate copolymerized with 20 mol% of adipic acid component and 10 mol% of isophthalic acid component), and the discharge rate was 10 kg / hr / cm ² . A laminated film having a thickness of 143 μm was obtained in the same manner as in Example 1 except that. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 3.1 μm, the layer thickness of layer number 267 is 5.5 μm, the layer thickness of layer number 535 is 6.1 μm, and the layer thickness of layer number 801 that is the outermost layer Was 3.3 μm, and all four layers were thick film layers of resin A. On the other hand, the thicknesses of the obtained resin A and B thin film layers were all in the range of 104 nm to 212 nm, and an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it was a transparent laminated film having a uniform high reflectance with few wave gaps (partial low reflection band) over a wavelength range of 900 nm to 1150 nm. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.1.
[Example 4]
Example 1 except that the resin B of Example 1 is replaced with a polyethylene terephthalate copolymer of IV = 0.75 (polyethylene terephthalate copolymerized with 10 mol% of naphthalenedicarboxylic acid component) and the slit length distribution is changed. In the same manner, a laminated film having a thickness of 91 μm was obtained. Each of the slit plates used here is formed by forming a slit length variation over the three slit plates used in Example 1 in one slit plate, and all the three slit plates have the same inclined slit length, A slit plate having a width distribution and a slit width for forming a thick film layer was also used. The slit width for forming the thick film layers positioned at both ends was designed to be 3.5 times the slit width for forming the other thin film layers. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of the layer number 1 that is the outermost layer is 4.5 μm, the layer thickness of the layer number 267 is 9.3 μm, the layer thickness of the layer number 535 is 9.5 μm, and the layer thickness of the layer number 801 that is the outermost layer Was 4.5 μm, and these four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin film layers of the obtained resins A and B were all in the range of 59 nm to 111 nm, and a generally inclined structure was realized for each thin film layer laminated by individual slits. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it is a laminated film with a metallic luster that has a wavelength of 450 nm to 600 nm, has few wave breaks (partial low reflection band), and has a uniformly high reflectance (60% or more). there were. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.08.
[Example 5]
A laminate having a thickness of 71 μm was obtained in the same manner as in Example 1 except that the resin B of Example 1 was replaced with a polyethylene terephthalate copolymer of IV = 0.75 (polyethylene terephthalate copolymerized with 15 mol% of diphenyldicarboxylic acid component). A film was obtained. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of the layer number 1 that is the outermost layer is 1.6 μm, the layer thickness of the layer number 267 is 2.7 μm, the layer thickness of the layer number 535 is 3.3 μm, and the layer thickness of the layer number 801 that is the outermost layer Was 1.8 μm, and these four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin film layers of the obtained resins A and B were all in the range of 32 nm to 110 nm, and generally realized a tilted structure. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it is a laminated film with a metallic luster that has a wavelength of 450 nm to 600 nm, has few wave breaks (partial low reflection band), and has a uniformly high reflectance (60% or more). there were. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.07.
[Example 6]
A laminated film having a thickness of 139 μm was obtained in the same manner as in Example 1 except that the discharge rate was 10 kg / hr / cm ² . A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 3 μm, the layer thickness of layer number 267 is 5.6 μm, the layer thickness of layer number 535 is 6.1 μm, and the layer thickness of layer number 801 that is the outermost layer is 3 The four layers were thick film layers of resin A. On the other hand, the thicknesses of the obtained resin A and B thin film layers were all in the range of 110 nm to 208 nm, and an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it is a transparent laminated film having a wave length (partial low reflection band) over a wavelength range of 900 nm to 1150 nm and having a uniformly high reflectance (90% or more). It was. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.11.
[Example 7]
A thickness of 66 μm was obtained in the same manner as in Example 6 except that a copolymer of polyethylene terephthalate having IV = 0.54 (polyethylene terephthalate copolymerized with 15 mol% of spiroglycol component and 30 mol% of cyclohexanedicarboxylic acid component) was used as resin B. A laminated film was obtained. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 1.6 μm, the layer thickness of layer number 267 is 2.8 μm, the layer thickness of layer number 535 is 3.3 μm, and the layer thickness of layer number 801 that is the outermost layer Was 1.7 μm, and these four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 42 nm to 105 nm, and an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it is a laminated film with a metallic luster feeling that has a wave length (partial low reflection band) over a wavelength range of 400 nm to 650 nm and has a uniform high reflectance (90% or more). there were. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.12.
[Example 8]
Resin B was replaced with a polyethylene terephthalate copolymer of IV = 0.72 (polyethylene terephthalate copolymerized with 25 mol% of isophthalic acid component), and a slit plate with 177 slits with a constant slit length and width was added. A laminated film having a thickness of 36 μm was obtained in the same manner as in Example 1 except that the laminated body was formed by laminating 353 layers alternately in the thickness direction by joining the 353-layer feed block having a configuration of using one sheet. However, in each slit plate used, the slit width for forming the thick film layers positioned at both ends was designed to be twice or more the slit width for forming the other thin film layers. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of the layer number 1 that is the outermost layer is 1.1 μm, the layer thickness of the layer number 177 is 3.1 μm, the layer thickness of the layer number 353 that is the other outermost layer is 1 μm, and the thickness of these three layers The film layers were all thick film layers of resin A. On the other hand, the thicknesses of the thin film layers of the obtained resins A and B were all in the range of 60 nm to 100 nm, and a periodic structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it was a laminated film having a high reflectance centered on a reflection wavelength of 550 nm. The shape of the spectral reflection spectrum was a single peak. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.08.
[Example 9]
A laminated film having a thickness of 136 μm was obtained in the same manner as in Example 1 except that only the slit width for forming the thick film layer of the slit plate of Example 1 was changed. However, in each of the slit plates used, the slit width for forming the thick film layers positioned at both ends was designed to be 5 times the slit width for forming the other thin film layers. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 12 μm, the layer thickness of layer number 267 is 22 μm, the layer thickness of layer number 535 is 26 μm, and the layer thickness of layer number 801 that is the outermost layer is 12 μm. All four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 65 nm to 121 nm, and it was confirmed that an inclined structure was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. It was confirmed that this was a laminated film with a metallic luster that had a wavelength of 450 nm to 600 nm with few wave gaps (partial low reflection band) and a uniform high reflectance (60% or more).
[Example 10]
A laminated film with a thickness of 132 μm was obtained by laminating 1601 layers by the same film forming method as in Example 1 except that one square mixer distributed 1: 0.9 was placed on the T die. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 which is the outermost layer is 1.3 μm, the layer thickness of layer number 267 is 3.0 μm, the layer thickness of layer number 535 is 3.1 μm, the layer thickness of layer number 801 is 3.5 μm, the layer The number 1067 has a layer thickness of 3.4 μm, the layer number 1335 has a layer thickness of 3.8 μm, and the outermost layer number 1601 has a layer thickness of 1.8 μm. These seven layers are thick film layers of the resin A. It was. On the other hand, the thin film layers of the obtained resins A and B were all in the range of 30 nm to 120 nm, and a layer thickness distribution in which two inclined structures were arranged was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. The obtained spectral reflection spectrum confirmed that the layer thickness distribution having a shape similar to that shown in FIG. 6 corresponds to the thickness of two layers arranged in the thickness direction. It was a laminated film with a metallic luster that had a wavelength of 400 nm to 660 nm, had few wave gaps (partial low reflection band), and uniformly high reflectivity (90% or more). However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.11.
[Example 11]
Resin B was changed to a polyethylene terephthalate copolymer of IV = 0.72 (polyethylene terephthalate copolymerized with 33 mol% of cyclohexanedimethanol), and the slit width of the thick film layer was changed and 1: 0. A laminated film having a thickness of 260 μm obtained by laminating 1601 layers was obtained by the same film forming method as in Example 1 except that one square mixer distributed to 95 was installed. However, in each slit plate used, the slit width for forming the thick film layers positioned at both ends was designed to be 2.0 times the slit width for forming the other thin film layers. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 which is the outermost layer is 2.3 μm, the layer thickness of layer number 267 is 3.0 μm, the layer thickness of layer number 535 is 3.1 μm, the layer thickness of layer number 801 is 6.5 μm, the layer The number 1067 has a layer thickness of 3.4 μm, the layer number 1335 has a layer thickness of 3.3 μm, and the outermost layer number 1601 has a layer thickness of 3.2 μm. These seven layers are thick film layers of the resin A. It was. On the other hand, the thicknesses of the obtained resin A and B thin film layers were all in the range of 102 nm to 205 nm, and a layer thickness distribution in which two inclined structures were arranged was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. The obtained spectral reflection spectrum confirmed that the layer thickness distribution having a shape similar to that shown in FIG. 6 corresponds to the thickness of two layers arranged in the thickness direction. Suitable for near-infrared cut filters with a wavelength ranging from 854 nm to 1106 nm with little wave drop (partial low reflection band), uniform high reflectivity (90% or more), and transparent color. It was a laminated film. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.085.
[Example 12]
A laminated film having a thickness of 63 μm was obtained in the same manner as Example 1. The laminated film and the laminated film of Example 1 were each laminated using a laminating machine to produce a laminated film with two sheets of adhesive. In the laminating method, a urethane adhesive dissolved in ethyl acetate was applied to one of the laminated films by a direct gravure method, and then dried in an oven at 60 ° C. and then bonded together with a lamellar roll at 60 ° C. The thickness of the obtained laminated film was 135 μm. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 which is the outermost layer is 1.1 μm, the layer thickness of layer number 267 is 2.8 μm, the layer thickness of layer number 535 is 3.0 μm, the layer thickness of layer number 801 is 1.4 μm, the layer The thickness of the adhesive of number 802 is 6 μm, the layer thickness of layer number 803 is 1.8 μm, the layer thickness of layer number 1067 is 3.3 μm, the layer thickness of layer number 1335 is 3.6 μm, and the layer number is the outermost layer The layer thickness of 1601 was 1.8 μm, and all the 8 layers except the adhesive were thick film layers of resin A. On the other hand, the thin film layers of the obtained resins A and B were all in the range of 30 nm to 120 nm, and a layer thickness distribution in which two inclined structures were arranged was realized. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. The obtained spectral reflection spectrum confirmed that the layer thickness distribution having a shape similar to that shown in FIG. 6 corresponds to the thickness of two layers arranged in the thickness direction. It was a laminated film with a metallic luster feeling having a wavelet (partial low reflection band) and a uniformly high reflectance (90% or more) over a wavelength range of 400 nm to 600 nm. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.11.
[Comparative Example 1]
Polyethylene terephthalate having IV = 0.65 was used as the resin A, and a copolymer of polyethylene terephthalate having IV = 0.75 (polyethylene terephthalate copolymerized with 30 mol% of cyclohexanedimethanol component) was used as the resin B. (Resin B is particle-free). Resins A and B were melted at 280 ° C. in respective extruders, passed through five FSS type leaf disk filters, and the discharge ratio was resin A composition / resin B composition = 1/1 by a gear pump. While being measured, the 801-layer feed block having a configuration using two slit plates having 267 slits and one slit plate having 269 slits is joined to form 801 layers alternately in the thickness direction. It was set as the laminated body laminated | stacked. None of the slit plates used formed a thick film layer, and the slit widths were all the same. The breakdown of the laminated structure is a laminated body having an inclined structure in which resin A is 401 layers and resin B is 400 layers alternately laminated in the thickness direction. Next, a square shape having an aspect ratio (length in the width direction / length in the thickness direction) of 1 was used as the cross-sectional shape of the polymer flow path from the feed block to the pinole. Moreover, the discharge amount of the laminated resin passing through the cross-sectional area within a unit time was 50 kg / hr / cm ² . Further, the resin C obtained by adding 0.06% by weight of aggregated silica having an average particle diameter of 1.2 μm to the resin A from the extruder C is merged from the pinol under the feed block so as to come to the outermost layer part, and a total of 801 layers It was set as the laminated body which consists of. The laminate was supplied to a T-die and formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic applied voltage of 8 kV with a wire to obtain an unstretched film. .
This unstretched film is longitudinally stretched at 100 ° C. and a stretching ratio of 3.5 times, led to a tenter that holds both ends with clips, 105 ° C. and 4.3 times transverse stretched, and then heat treated at 230 ° C., TD relaxation of about 5% was performed at 120 ° C. to obtain a laminated film having a thickness of 65 μm. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 1.7 μm, the layer thickness of layer number 801 that is the other outermost layer is 1.5 μm, and the thick film layer of resin A is 2 in total. It was a layer. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 40 nm to 124 nm, but the phenomenon that the layer thickness at the beginning and the end of the layer number was reduced (thinning of the surface layer). The layer thickness distribution structure was observed. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. It was confirmed that the obtained spectral reflection spectrum had a shape similar to FIG. That is, it was confirmed that the film was a laminated film having a poor optical performance with many wave gaps having a reflectance of less than 50% over a wavelength range of 425 nm to 575 nm. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.08.
[Comparative Example 2]
Except for using a slit plate with a slit number of 201 having a constant slit width and length, reducing the cross-sectional area of the polymer flow path, and setting the discharge amount to 50 kg / hr / cm ² , the same as in Example 8. A laminated film having a thickness of 17 μm was obtained. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. No thick film layer of 1 μm or more was found. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 21 nm to 126 nm, and had an upwardly convex layer thickness distribution structure. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. From the result of the obtained spectral reflection spectrum, it was confirmed that the film was a laminated film having a spectral reflection spectrum in which the reflection wavelength bandwidth was expanded centering on the reflection wavelength 551 nm. Moreover, the shape of the spectral reflection spectrum was a spectral reflection spectrum in which a side peak was confirmed on the lower wavelength side of the main peak. However, the in-plane refractive index difference (absolute value) between the resins A and B was 0.08.
[Comparative Example 3]
A laminated film having a thickness of 172 μm was obtained in the same manner as in Example 1 except that only the slit width for forming the thick film layer of the slit plate of Example 2 was changed. A cross section in the thickness direction of the obtained laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thickness of layer number 1 that is the outermost layer is 15 μm, the layer thickness of layer number 267 is 33 μm, the layer thickness of layer number 535 is 31 μm, and the layer thickness of layer number 801 that is the outermost layer is 17 μm. All four layers were thick film layers of resin A. On the other hand, the thicknesses of the thin films of the obtained resins A and B were all in the range of 42 nm to 190 nm, and a layer thickness distribution structure in which surface layer thinning was observed. The laminated structure and physical property results of the obtained laminated film are shown in Table 1. In the spectral reflection spectrum, it was confirmed that the film was a laminated film having many wave gaps with reflectance of less than 50% and poor optical performance.

The present invention relates to a laminated film. More specifically, design materials used for mobile phones, home appliances, building materials, packaging, automobile interior and exterior, anti-counterfeiting materials such as holograms used for securities, liquid crystal displays, plasma displays, field emission displays, Reflective materials or optical filters for various displays such as organic electronics displays, optical printing equipment, cameras, light guides, optical communications, heat ray blocking window films for automobiles and building materials, reflectors for solar cells, etc. The present invention relates to a suitable laminated film.

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 Schematic diagram of merging device Schematic diagram of square mixer Explanatory drawing of an example of the laminated structure of this invention Spectral reflection spectrum of broadband reflection film without wave gap Spectral reflection spectrum of a broadband reflection film with severe wave breakage.

Explanation of symbols

1: member plate 2: resin introduction plate 3: slit plate 4: resin introduction plate 5: slit plate 6: resin introduction plate 7: slit plate 8: resin introduction plate 9: member plate 10: feed block 11: introduction port 12: Liquid reservoir 13: Ridge line at the top of each slit 14: Upper end part of the ridgeline at the top part of each slit 15: Lower end part of the ridgeline at the top part of each slit 16: Resin introduced into the slit 17: Outlet 18: Junction device 19L : Outlet 20L of the slit plate 3: Outlet 21L of the slit plate 5: Outlet 19M of the slit plate 7: Cross section shape 20M of the flow path rearranged from the outflow port of the slit plate 3 by restriction of the flow path 20: Slit plate Cross-sectional shape 21M of the flow path rearranged by restriction of the flow path from the outlet of 5: Cross-sectional shape 19N of the flow path rearranged by restriction of the flow path from the outlet of the slit plate 7: of the widened flow path Cross-sectional shape 20N: Cross-sectional shape of the widened channel 21N: Cross-sectional shape of the widened channel 22: Square mixer 23O: One divided square mixer inlet 23P: One divided polymer channel 23Q in the square mixer: Divided One square mixer outlet 24O: The other divided square mixer inlet 24P: The other divided polymer flow path 24Q in the square mixer: The other divided square mixer outlet 25: By the slit plate 1 Layer thickness distribution 26 produced: Layer thickness distribution 27 produced by slit plate 2 27: Layer thickness distribution produced by slit plate 3 28: Layer thickness distribution 29 of resin A in slit plate 3 29: Thick film layer 30: Layer thickness distribution 31 for 10 thin film layers of resin A with average layer thickness D2 (nm): Resin A with average layer thickness D1 (nm) Thin layer 10 layer worth of layer thickness distribution 32: layer thickness distribution of the resin A in the slit plate 2 33: layer thickness distribution of the resin A in the slit plate 1 34: partial wave loss region

Claims (7)

The feed block for laminating at least two kinds of resins in multiple layers has a structure using two or more slit plates. In the slit plate, the slit width for forming the thick film layers located at both ends is other thin film layers. The film is manufactured using a feed block that is twice or more the slit width forming the film, and the film is laminated in a thickness direction of 250 layers or more, and a thick film layer having a thickness of at least 1 μm to 30 μm. A laminated film containing three or more layers and having a maximum reflectance of 60% or more at a wavelength of 250 to 2600 nm. 2. The thin film layer having a thickness of 0.01 or more and 0.4 μm or less is included between at least 50 thick film layers at least on the outermost layer, and between adjacent thick film layers in the permutation of the thick film layers. Laminated film. In the distribution of the layer number and the layer thickness in the thin film layer of at least one kind of resin of the laminated film, the layer thickness average of 30 thin film layers from one outermost layer side is E1 (nm), and the other outermost layer side is When the layer thickness average of 30 thin film layers is E2 (nm) and the layer thickness average of 30 thin film layers in the central portion in the thickness direction is C (nm), the following formula (1), (2) The laminated film according to claim 1 or 2, which satisfies the formula simultaneously.
E1 ≧ C ≧ E2 (1)
0.9 ≧ E2 / E1 ≧ 0.3 Formula (2) In the thin film layer region sandwiching the thick film layer, the thin film layers of 10 layers from the thick film layer side to the top and bottom in the thickness direction, the average layer thicknesses being D1 (nm) and D2 (nm), respectively, When the average layer thickness of the thin film layer from the film layer side to the next thick film layer up and down in the thickness direction is R1 (nm) and R2 (nm), respectively, the following expressions (3) and (4) The laminated film according to any one of claims 1 to 3, which simultaneously satisfies the formula.
R1 ≧ R2 Formula (3)
D1 ≦ D2 (Formula 4) The laminated film according to any one of claims 1 to 4, which is produced using a square mixer. The laminated film according to any one of claims 1 to 5, wherein a layer comprising polyethylene terephthalate and a layer comprising polyester comprising spiroglycol and cyclohexanedicarboxylic acid are laminated. The laminated film according to any one of claims 1 to 6, which is produced by a film production method using a T die.

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