JP2012030563A - Laminated film and automotive window glass using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film having heat-ray screening performance superior to a conventional polymer multilayer film while suppressing the change of color tint due to the subtle difference in an incident angle of light or a film thickness.SOLUTION: The laminated film has a composition in which two or more types of thermoplastic resins having different optical properties are mutually laminated for ≥50 layers, an average reflectance in wavelength 400-700 nm is ≥20% and less than 40%, and the average reflectance of wavelength 900-1,200 nm is ≥70%.

Description

  The present invention relates to a laminated film, and relates to a laminated film that can suppress an increase in internal temperature due to sunlight when used in a window glass of an automobile, a train, or a building.

  In recent years, under the restriction of carbon dioxide emission due to environmental protection, hot-wire cut glass that can suppress the inflow of heat from the outside of the summer, especially sunlight, has been attracting attention as a vehicle and window glass for buildings.

  As an example of such a heat ray cut glass, a heat ray absorbing material contained in an intermediate film used in glass or laminated glass is known (for example, Patent Document 1). However, since the heat ray absorbing material converts sunlight incident from the outside into heat energy, there is a problem that the heat is radiated into the room and the heat ray cutting efficiency is lowered. In addition, the glass temperature partially increases by absorbing the heat rays, and the glass body may be damaged due to the difference from the outside air temperature.

  On the other hand, a heat ray reflective glass in which a heat ray reflective film is formed on glass or a film having a heat ray reflective function is inserted into laminated glass is also known. In this case, since incident light including infrared rays is reflected to the outside, it does not flow into the room as light and heat, and heat rays can be blocked more effectively. Moreover, since the raise of the glass temperature by a heat ray is also suppressed, breakage of glass can also be suppressed.

  As a typical example of such heat ray reflective glass, there is a method of forming a metal film on the glass surface by sputtering or the like (for example, Patent Document 2). However, the metal film has a problem that although it reflects heat rays, it has a non-uniform reflection in visible light, and further, the reflection intensity varies depending on the wavelength, resulting in coloring. Further, since the visible light region and the near infrared region cannot be selectively reflected, it is difficult to improve the heat ray cutting performance while maintaining the visible light transmittance. Furthermore, since the metal film has a property of blocking radio waves, a device such as a mobile phone may become unusable.

  Further, as another example of the heat ray reflective glass, a laminated glass sandwiching a polymer multilayer laminated film in which polymers having different refractive indexes are alternately laminated is known (for example, Patent Document 3). Since such a polymer multilayer laminated film can selectively select the wavelength to be reflected by controlling the layer thickness, it can selectively reflect light in the near-infrared region, while maintaining visible light transmittance. The heat ray cutting performance can be improved. In addition, since it does not include metal or other materials that block radio waves, it has excellent radio wave permeability. However, in the case of using such a multilayer laminated film, only a part of sunlight can be reflected, and the heat ray cutting performance cannot be improved unless a part of visible light can be reflected.

JP 2010-17854 A Japanese Patent No. 3901911 Japanese Patent No. 4310312

  This invention makes it a subject to provide the laminated | multilayer film provided with the heat ray cut performance superior to the conventional polymer multilayer laminated film in view of the trouble of the above-mentioned prior art.

  In order to solve the problem, the present invention is intended to provide a laminated film including the following configuration. Various improved aspects thereof are also provided.

  That is, it includes a configuration in which 50 or more layers of two or more thermoplastic resins having different optical properties are alternately laminated, and the average reflectance at a wavelength of 400 to 700 nm is 20% or more and less than 40%, and The gist of the present invention is a laminated film having an average reflectance of 70% or more at a wavelength of 900 to 1200 nm.

  According to the present invention, it is possible to obtain a laminated film having heat ray cutting performance superior to that of a conventional polymer multilayer laminated film by reflecting light in a visible light region that occupies most of sunlight. Moreover, when it uses as a window of a motor vehicle, a train, and a building, the indoor temperature rise by sunlight can be suppressed.

It is explanatory drawing explaining an example of the manufacturing method of the laminated | multilayer film used for this invention, (a) is a schematic front view of an apparatus, (b), (c), (d) is LL ', MM, respectively. It is sectional drawing of the resin flow path cut | disconnected by ', NN'. It is an example of the relationship between the order of layers of the laminated film used in the present invention and the layer thickness (layer thickness distribution), and is an example of a laminated film having three inclined structures based on the concept of λ / 4 design. It is an example of the relationship between the order of layers in the laminated film used in the present invention and the layer thickness (layer thickness distribution), and is an example of a laminated film having two inclined structures based on the idea of an equivalent film.

  Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not construed as being limited to the embodiments including the following examples, and the objects of the present invention can be achieved. Of course, various modifications can be made without departing from the scope of the invention.

  The laminated film of the present invention needs to be made of a thermoplastic resin. Thermoplastic resins are generally cheaper than thermosetting resins and photocurable resins, and can be easily and continuously formed into sheets by known melt extrusion, so that a laminated film can be obtained at low cost. Is possible.

  In the laminated film of the present invention, it is necessary that 50 or more layers of thermoplastic resins having at least two different optical properties are alternately laminated. The different optical properties referred to here mean that the refractive index is different by 0.01 or more in either of two orthogonal directions arbitrarily selected in the plane of the heat ray cut film and a direction perpendicular to the plane. The term “alternately laminated” as used herein means that layers made of different resins are laminated in a regular arrangement in the thickness direction, for example, two thermoplastic resins A and B having different optical properties. When each layer is expressed as an A layer and a B layer, the layers are stacked in a regular arrangement of A (BA) n (n is a natural number). By alternately laminating resins with different optical properties in this way, it is possible to express interference reflection that can reflect the light of the designed wavelength from the relationship between the refractive index difference of each layer and the layer thickness. It becomes. In addition, when the number of layers to be stacked is less than 50 layers, high reflectance cannot be obtained over a sufficient band in the infrared region, and sufficient heat ray cutting performance cannot be obtained. Preferably, it is 400 layers or more, More preferably, it is 800 layers or more. The interference reflection described above can achieve a high reflectance with respect to light in a wider wavelength band as the number of layers increases, and a laminated film having a high heat ray cutting performance can be obtained. In addition, although there is no upper limit to the number of layers, as the number of layers increases, the manufacturing cost increases due to an increase in the size of the manufacturing apparatus, and the handling properties deteriorate due to the increase in film thickness, and in particular the film thickness increases. Then, since it may cause a process failure in the process of forming the laminated glass, in reality, about 10,000 layers are within the practical range.

  The thermoplastic resins used in the present invention are chain polyolefins such as polyethylene, polypropylene, poly (4-methylpentene-1), polyacetal, and ring-opening metathesis polymerization of norbornenes, addition polymerization, and addition copolymerization with other olefins. Biodegradable polymers such as alicyclic polyolefin, polylactic acid, and polybutyl succinate, polyamides such as nylon 6, nylon 11, nylon 12, and nylon 66, aramid, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride , Polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglycolic acid, polystyrene, styrene copolymer polymethyl methacrylate, polycarbonate, polypropylene terephthalate, polyethylene terephthalate Polyester, polybutylene terephthalate, polyethylene-2,6-naphthalate, etc., polyethersulfone, polyetheretherketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene resin, A trifluorinated ethylene resin, a trifluorinated ethylene resin, a tetrafluoroethylene-6 fluoropropylene copolymer, polyvinylidene fluoride, or the like can be used. Of these, polyester is particularly preferred from the viewpoint of strength, heat resistance, transparency and versatility. These may be a copolymer or a mixture.

  The polyester is preferably a polyester obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol. Here, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyl Examples include dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, and the like. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid and ester derivatives thereof. Of these, terephthalic acid and 2,6 naphthalenedicarboxylic acid exhibiting a high refractive index are preferable. These acid components may be used alone or in combination of two or more thereof, and further may be partially copolymerized with oxyacids such as hydroxybenzoic acid.

  Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4- Hydroxyethoxyphenyl) propane, isosorbate, spiroglycol and the like. Of these, ethylene glycol is preferably used. These diol components may be used alone or in combination of two or more.

  The thermoplastic resin of the present invention is, for example, among the above polyesters, polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, Furthermore, it is preferable to use polyhexamethylene terephthalate and its copolymer, polyhexamethylene naphthalate and its copolymer, and the like.

  In the laminated film of the present invention, among the thermoplastic resins having different optical properties, it is preferable that the difference in the in-plane average refractive index of each layer composed of at least two thermoplastic resins is 0.03 or more. More preferably, it is 0.05 or more, More preferably, it is 0.1-0.15. When the difference in the in-plane average refractive index is smaller than 0.03, sufficient reflectivity cannot be obtained, so that the heat ray cutting performance may be insufficient. As a method for achieving this, at least one thermoplastic resin is crystalline and at least one thermoplastic resin is amorphous. In this case, it is possible to easily provide a refractive index difference in the stretching and heat treatment steps in film production.

  As a preferable combination of the thermoplastic resins having different optical properties used in the laminated film of the present invention, it is first preferable that the absolute value of the difference in SP value of each thermoplastic resin is 1.0 or less. When the absolute value of the difference in SP value is 1.0 or less, delamination hardly occurs. More preferably, the polymers having different optical properties are preferably composed of a combination provided with the same basic skeleton. The basic skeleton here is a repeating unit constituting the resin. For example, when polyethylene terephthalate is used as one thermoplastic resin, it is the same as polyethylene terephthalate from the viewpoint of easily realizing a highly accurate laminated structure. It is preferable to contain ethylene terephthalate which is a basic skeleton of When the thermoplastic resins having different optical properties are resins containing the same basic skeleton, the lamination accuracy is high, and delamination at the lamination interface is less likely to occur.

  Moreover, as a preferable combination of the thermoplastic resins having different optical properties used in the laminated film of the present invention, the glass transition temperature difference of the thermoplastic resins is preferably 20 ° C. or less. When the glass transition temperature difference is larger than 20 ° C., the thickness uniformity at the time of forming the laminated film becomes poor and the appearance of metallic luster becomes poor. Also, when a laminated film is formed, problems such as overstretching tend to occur.

  As an example of a combination of resins for satisfying the above conditions, in the laminated film of the present invention, at least one thermoplastic resin contains polyethylene terephthalate or polyethylene naphthalate, and at least one thermoplastic resin contains spiroglycol. It is preferable that it is polyester consisting of. The polyester comprising spiroglycol refers to a copolyester copolymerized with spiroglycol, a homopolyester, or a polyester blended with them. Polyesters containing spiroglycol are preferred because they have a small glass transition temperature difference from polyethylene terephthalate or polyethylene naphthalate, so that they are not easily stretched at the time of molding and are also difficult to delaminate. More preferably, at least one thermoplastic resin comprises polyethylene terephthalate or polyethylene naphthalate, and at least one thermoplastic resin is preferably a polyester comprising spiroglycol and cyclohexanedicarboxylic acid. In the case of a polyester comprising spiroglycol and cyclohexanedicarboxylic acid, the in-plane refractive index difference from polyethylene terephthalate or polyethylene naphthalate is increased, so that high reflectance is easily obtained. Moreover, since the glass transition temperature difference with polyethylene terephthalate or polyethylene naphthalate is small and the adhesiveness is excellent, it is difficult to be over-stretched at the time of molding and is also difficult to delaminate.

  In the laminated film of the present invention, it is preferable that at least one thermoplastic resin comprises polyethylene terephthalate or polyethylene naphthalate, and at least one thermoplastic resin comprises polyester comprising cyclohexanedimethanol. The polyester comprising cyclohexanedimethanol refers to a copolyester obtained by copolymerizing cyclohexanedimethanol, a homopolyester, or a polyester obtained by blending them. Polyesters containing cyclohexanedimethanol are preferred because they have a small glass transition temperature difference from polyethylene terephthalate or polyethylene naphthalate, so that they are unlikely to be overstretched during molding and are also difficult to delaminate. More preferably, at least one thermoplastic resin is an ethylene terephthalate polycondensate having a copolymerization amount of cyclohexanedimethanol of 15 mol% or more and 60 mol% or less. In this way, while having high reflection performance, the change in optical characteristics due to heating and aging is particularly small, and peeling between layers is less likely to occur. An ethylene terephthalate polycondensate having a copolymerization amount of cyclohexanedimethanol of 15 mol% or more and 60 mol% or less adheres very strongly to polyethylene terephthalate. In addition, the cyclohexanedimethanol group has a cis or trans isomer as a geometric isomer, and a chair type or a boat type as a conformational isomer. In addition, the change in optical characteristics due to thermal history is even less, and blurring during film formation hardly occurs.

  In the laminated film of the present invention, the average reflectance at a wavelength of 400 to 700 nm needs to be 20% or more and less than 40%. Sunlight has a large intensity distribution particularly in the visible light region having a wavelength of 400 to 700 nm, and occupies about 44% of the intensity of total sunlight. For this reason, when the average reflectance at a wavelength of 400 to 700 nm is less than 20%, the transmittance of visible light is improved, but conversely, the performance of reflecting sunlight in the visible light region is inferior, so the heat ray cutting performance is There is a limit. On the other hand, at a wavelength of 400 to 700 nm, it occupies about 81% of the intensity of all visible light, so that the reflectance in the region increases, that is, the transmittance decreases, so that the window glass of automobiles, trains, buildings, etc. In applications where high transparency is required, the visible light transmittance is insufficient, and it cannot be used as a window glass. Therefore, in order to maintain a sufficient visible light transmittance, the average reflectance at a wavelength of 400 to 700 nm needs to be less than 40%. When the average reflectance at a wavelength of 400 to 700 nm is 20% or more and less than 40%, high heat ray cutting performance can be imparted while maintaining sufficient transparency. More preferably, the average reflectance at a wavelength of 400 to 700 nm is 25% or more and less than 35%. In this case, it is possible to show high heat ray cutting performance even in applications that require extremely high transparency, such as automobile windshields.

  In the laminated film of the present invention, the average reflectance at a wavelength of 900 to 1200 nm needs to be 70% or more. As described above, sunlight has an intensity distribution mainly in the visible light region, and the intensity distribution tends to decrease as the wavelength increases. Therefore, the higher the average reflectance at a wavelength 900 to 1200 nm (about 18% of the intensity of total sunlight) slightly larger than the visible light region, the more efficiently the heat ray cutting performance can be improved. When the average reflectance at a wavelength of 900 to 1200 nm is less than 70%, the heat ray cutting performance is not sufficient, which is not preferable. Preferably, the average reflectance at a wavelength of 900 to 1200 nm is 80% or more, and more preferably the average reflectance at a wavelength of 900 to 1200 nm is 90% or more. As the average reflectance at a wavelength of 900 to 1200 nm increases, high heat ray cutting performance can be imparted.

  In the laminated film of the present invention, it is preferable that the difference between the maximum reflectance and the minimum reflectance at 100 nm continuous within a wavelength of 400 to 700 nm is less than 10%. In the visible light region having a wavelength of 400 to 700 nm, a slight difference in reflectance at each wavelength causes a difference in color. Moreover, in the laminated film as in the present invention, the reflection wavelength changes depending on the slight difference in the incident angle of light and the film thickness, and the color changes depending on the slight difference in reflectance. In particular, in a window glass application, since it is necessary to visually recognize objects at various angles, it is required that the color change due to the incident angle of light is smaller. In the case where the difference between the maximum reflectance and the minimum reflectance at 100 nm that is continuous within a wavelength range of 400 to 700 nm is less than 10%, it is possible to suppress changes in color due to the film thickness and the incident angle of light. The film is suitable for use. Preferably, the difference between the maximum reflectance and the minimum reflectance at 100 nm which is continuous at least in the wavelength range of 400 to 700 nm is less than 5%. In this case, the color difference due to the difference in the film thickness or the difference in the incident angle of light The difference can hardly be confirmed. As another preferred mode, the difference between the maximum reflectance and the minimum reflectance in the entire region at a wavelength of 400 to 700 nm may be less than 10%. In this case, in order to show a substantially uniform reflectance over the entire visible light region, the coloration of the film itself can be suppressed, and the film is almost uncolored regardless of the difference in film thickness or the incident angle of light. . In order to obtain such a laminated film, it is desirable that light having a wavelength of 400 to 700 nm can be reflected using a layer thickness distribution having a plurality of inclined structures as described later.

  In the laminated film of the present invention, the C * value of transmitted light is 5 or more, and the signs of the a * value and b * value at the incident angle of 0 ° and the incident angle of 45 ° are the same. preferable. As mentioned above, when the color changes depending on the film thickness and the incident angle of light, there is a problem with the window glass, but the C * value of the transmitted light is 5 or more, and the incident angle is 0 ° and the incident angle. When the signs of the a * value and the b * value at 45 ° are the same, a stable color can be obtained regardless of a slight difference in film thickness or light incident angle, and it is used as a window glass. It becomes a suitable thing. As a method for achieving this, in any region of visible light having a wavelength of 400 to 700 nm, a region having a reflectance higher by 5% or more than the average reflectance of 400 to 700 nm in at least a continuous 50 nm range is provided. preferable. In this case, since the color tone of light in a wavelength band having a high reflectance is mainly used, there is an effect that it is possible to suppress a change in the color tone due to the difference in the incident angle of the light and the film thickness. More preferably, the reflectance at 600 to 700 nm is preferably 5% or more higher than the reflectance at 400 to 600 nm. In this case, since the light of 600 nm or more having a relatively small influence on the visible light transmittance is reflected more, it is possible to suppress a change in the color of the transmitted light while suppressing a decrease in the visible light transmittance.

In the laminated film of the present invention, the solar reflectance is preferably 40% or more. The solar reflectance referred to herein is a _{R DS} defined in ISO 9050. When the solar reflectance is 40% or more, it is possible to impart high heat ray cutting performance while suppressing breakage of glass due to absorption of heat rays. This can be achieved when the average reflectance at a wavelength of 400 to 700 nm is 20% or more and less than 40% and the average reflectance at a wavelength of 900 to 1200 nm is 70% or more. More preferably, the solar reflectance is 40% or more and the visible light transmittance is 70% or more, and more preferably, the solar reflectance is 50% or more and the visible light transmittance is 70% or more. The visible light transmittance referred to herein is a _{T VIS} defined by ISO 9050. It goes without saying that the heat ray cutting performance is superior as the solar reflectance increases, but it can also be applied to those that require high transparency, such as automobile windshields, because the visible light transmittance is 70% or more. It will be. In order to achieve this, in particular, in addition to controlling the reflectance at a wavelength of 400 to 700 nm to 30% or more and 40% or less, it can be achieved by providing a reflection performance to a wavelength of 1200 nm or more by a design method described later. is there.

  The laminated film of the present invention includes at least one component laminated element (Ln) in which two or more kinds of thermoplastic resins having different optical properties that reflect light having a wavelength of 900 to 1200 nm are alternately laminated, and has a wavelength. It is preferable to include at least one component laminated element (Lv) in which two or more kinds of thermoplastic resins having different optical properties that reflect light of 400 to 700 nm are alternately laminated. The term “constitutive laminated element” as used herein refers to a distribution of a series of layers that reflect light of a prescribed wavelength. Further, when using higher-order interference reflection as described later, the functions of the constituent laminated elements Ln and Lv can be achieved by one layer group in which the layer thickness continuously changes. By providing such a structural laminated element (Ln, Lv), light at wavelengths of 400 to 700 nm and wavelengths of 900 to 1200 nm can be reflected.

  As a more preferable form of the laminated film, the number of layers contained in the constituent laminated element Ln is a laminated film larger than the number of layers contained in the constituent laminated element Lv. In this case, for example, when each constituent layer is made of the same resin combination, the reflectance at a wavelength of 900 to 1200 nm can be achieved rather than the reflectance at a wavelength of 400 to 700 nm. The average reflectance is 20% or more and less than 40%, and the average reflectance at a wavelength of 900 to 1200 nm can be 70% or more. One of the advantages in this case is that the heat ray cutting performance can be increased without unnecessarily increasing the thickness of the film, resulting in a decrease in handling properties due to an increase in the thickness of the film and occurrence of molding defects in the laminated glass forming process. Can be suppressed.

  Further, as a preferred laminated film form, a laminated film in which the in-plane average refractive index difference of each layer constituting the constituent laminated element Ln is 0.01 or more larger than the in-plane average refractive index difference of each layer constituting the constituent laminated element Lv Is mentioned. At this time, if the number of layers is the same, the reflectance in the component laminated element Ln having a large in-plane average refractive index difference is larger, and the average reflectance at a wavelength of 400 to 700 nm is 20% or more and less than 40%, And the average reflectance in wavelength 900-1200nm can achieve 70% or more. As an advantage in this case, the physical properties of the laminated film can be controlled by using different thermoplastic resins, and a film more suitable for the laminated glass forming process can be obtained.

  As a method for providing the constituent laminated elements as described above, a layer thickness distribution corresponding to each constituent laminated element can be provided by a laminating apparatus including a feed block described later. However, in the laminated film of the present invention, it is also preferable that an adhesive layer exists between the constituent laminated element Ln and the constituent laminated element Ln. The laminated film of the present invention tends to have a large number of layers in order to reflect a very wide band of light. As the number of layers increases, disorder of the layer thickness is likely to occur during the flow in the laminating apparatus, and it may be difficult to obtain a laminated film having a desired layer thickness distribution. In addition, in the case where the constituent laminating element Ln and the constituent laminating element Lv are made of a combination of different thermoplastic resins, the construction of the laminating apparatus becomes complicated or large when trying to obtain a film in one laminating apparatus. In some cases, the cost of the manufacturing apparatus, the manufacturing space, and the reduction in stacking accuracy may occur. However, when different films are pasted together via an adhesive layer, it becomes possible to obtain a laminated film that is easily laminated with high precision using a smaller apparatus, and a laminated film having a desired heat ray cutting performance is obtained. .

  The layer thickness of the laminated film of the present invention is such that layers (A layer) made of thermoplastic resin A and layers (B layer) made of thermoplastic resin B having optical properties different from those of thermoplastic resin A are laminated alternately. In such a case, the reflectance is determined according to the following formula 1. Normally, the laminated film used for this purpose is designed to reflect light having a wavelength of 900 to 1200 nm by designing the optical thickness ratio k defined by the following formula 2 to be 1. The secondary reflection of the component laminated element Ln is suppressed. However, in the laminated film of the present invention, it is also preferable that the optical thickness ratio is 1.25 or more. In this case, by intentionally introducing secondary reflection, it becomes possible to reflect light having a wavelength of 450 to 600 nm using a layer that reflects light having a wavelength of 900 to 1200 nm. As a result, it is possible to provide high heat ray cutting performance even with a smaller number of layers. More preferably, the layer having a large optical thickness is made of an amorphous thermoplastic resin. In this case, while imparting high heat ray cutting performance, it is possible to suppress the stress at the time of stretching that occurs in the curved surface portion of the window glass in the laminated glass process, and it is possible to suppress molding defects in the laminated glass process. .

2 × (na · da + nb · db) = λ Equation 1
| (Na · da) / (nb · db) | = k Equation 2
na: In-plane average refractive index of the A layer nb: In-plane average refractive index of the B layer da: Layer thickness (nm) of the A layer
db: Layer thickness of layer B (nm)
λ: main reflection wavelength (primary reflection wavelength)
k: Ratio of optical thickness Further, in the laminated film of the present invention, a layer (A layer) made of thermoplastic resin A and a layer (B layer) made of thermoplastic resin B having optical properties different from those of thermoplastic resin A It is also preferable that the layer thicknesses of the A layer and the B layer consist of repetitions of 6 layer units laminated at a ratio of 1: X: 1: 1: X: 1. An example of such a layer thickness distribution is shown in FIG. This design concept is mainly based on the idea of an equivalent film. In this case, when the reflection wavelength is set to 1200 nm or more for the third-order reflection in the normal λ / 4 design shown in the above formula 1, the wavelength is 400 nm. Reflection occurs even in the above visible light region, but higher-order reflection can be suppressed. Therefore, even when a reflection wavelength of 1200 nm or more is provided, occurrence of reflection in the visible light region can be suppressed, and higher heat ray cut Performance can be imparted. The longest reflection wavelength is preferably a wavelength of 1200 to 2000 nm, and more preferably a wavelength of 1600 to 2000 nm. The longest reflection wavelength here refers to a portion having the longest wavelength among the wavelengths having a reflectance of 20% or more. In this case, high heat ray cutting performance that cannot be obtained with a normal laminated film can be imparted.

  Further, as a more preferable form, it is also preferable that the layer thickness coefficient X is 5 or more and 6 or less, or 8 or more and 9 or less. In this case, since controlled reflection can be introduced into the visible light region, it is possible to give a very high heat ray cutting performance by increasing the bandwidth by reflecting light having a wavelength of 1200 nm or more and reflecting visible light, and increase the number of layers. Therefore, it becomes possible to suppress a decrease in handling performance. More preferably, the layer thickness coefficient X is 5 or more and 6 or less. In this case, since the increase in the film thickness accompanying the increase in the number of layers can be suppressed to a minimum, it becomes possible to suppress a decrease in handling properties and a molding defect in the laminated glass forming step.

  In the laminated film of the present invention, the thermal shrinkage rate when heated at 140 ° C. for 30 minutes is preferably ± 1% or less. In the laminated vitrification step, generally, a step of thermocompression bonding of two sheets of glass and a laminated film through an intermediate film such as polyvinyl butyral is performed in the range of 100 to 140 ° C. At this time, if a laminated film having a large heat shrinkage rate is used, wrinkles may occur in the film as a result of the heat shrinkage, which may cause molding defects. As this achievement method, it can be achieved by a method of relaxation treatment of the film after the heat treatment in the film forming step described later.

  Moreover, in the laminated | multilayer film of this invention, it is preferable that the 5% stress at the time of extending | stretching at 140 degreeC is 10 Mpa or less. In this case, in the laminated glass forming step, since the glass can be flexibly followed by a curved surface portion, a laminated glass with good quality can be obtained. This is achieved by increasing the layer thickness of the ratio of layers including amorphous thermoplastic resin when using thermoplastic resins with different optical properties. it can. As the ratio of the amorphous thermoplastic resin becomes larger than that of the crystalline thermoplastic resin, the stress generated in the thermocompression bonding process can be suppressed.

  Next, a preferred method for producing the laminated film of the present invention will be described below by taking a laminated film made of thermoplastic resins A and B as an example.

  Two types of thermoplastic resins A and B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to a separate extruder. In the extruder, the resin melted by heating to a temperature equal to or higher than the melting point is made uniform in the amount of resin extruded by a gear pump or the like, and foreign matter or denatured resin is removed through a filter or the like.

  The thermoplastic resins A and B sent out from different flow paths using these two or more extruders are then fed into the laminating apparatus. As the laminating apparatus, a multi-manifold die, a feed block, a static mixer, or the like can be used. Particularly, in order to efficiently obtain the configuration of the present invention, at least two members having a large number of fine slits are separately provided. It is preferred to use a feed block that contains.

  The laminated structure of the laminated film used in the present invention can be easily realized by the same method as described in the paragraphs [0053] to [0063] of JP-A-2007-307893. However, the gap and length of the slit plate are different because of design values that determine the layer thickness. Hereinafter, a process of making a laminated structure will be described with reference to FIG. In FIG. 1, X indicates the film width direction, and Y indicates the film thickness direction.

  The laminating apparatus 7 has the same three slit plates as the apparatus described in Japanese Patent Application Laid-Open No. 2007-307893. An example of the layer thickness distribution of the laminated structure obtained by the laminating apparatus 7 is shown in FIG. When the horizontal order is the layer arrangement order 18 and the vertical axis is the thickness (nm) 19 of each layer, the laminated structure is formed by the inclined structure 11 and the slit plate 72 of the layer thickness by the resin laminate flow formed by the slit plate 71. The inclined structure 12 of the layer thickness by the laminated flow of the formed resin and the inclined structure 13 of the layer thickness by the laminated flow of the resin formed by the slit plate 73 are provided. Moreover, it is preferable that at least one inclined structure is opposite in direction to any other inclined structure. Furthermore, from the viewpoint of suppressing a flow mark due to an unstable phenomenon of the resin flow, a thick film layer 20 having a thickness of 1 μm or more is provided on the outermost layer. The inclined structure formed from one slit plate is composed of a layer thickness distribution 21 of resin A and a layer thickness distribution 22 of resin B, and the ratio of the layer thicknesses is the resin A and resin B of two extruders. It can be easily adjusted by the ratio of the amount of extrusion. The ratio of the layer thickness is determined by the ratio of the total thickness of the thermoplastic resin A layer excluding the thick film layer and the total thickness of the thermoplastic resin B layer. Each layer thickness is calculated | required by observing a lamination | stacking cross section with a transmission electron microscope. Moreover, since the thickness of each layer also changes proportionally by adjusting the overall thickness, the absolute value of the layer thickness can be adjusted. In addition, the average layer thickness here is an average of the layer thicknesses of the adjacent A layer and B layer. For example, in the layer thickness distribution of 601 layers, B1, A1, B2, A2, B3,..., A299, B300 and the respective layers in the remaining 599 thin film layers excluding the outermost two thick film layers. Are arranged, the average layer thickness distribution is the layer thickness distribution obtained by sequentially plotting the average of Bm and Am (m is an integer), such as the average of B1 and A1, and the average of B2 and A2. Become.

  Further, FIG. 3 shows the repetition of the 6-layer unit in which the layer thicknesses of the A layer and the B layer are laminated at a ratio of 1: X: 1: 1: X: 1. 1 (A layer): X (B layer): 1 (A layer): 1 (B layer): X (A layer): 1 (B layer) As can be seen, a layer having a large layer thickness appears at a ratio of one layer to three layers, and the layer thickness changes with a constant gradient.

  The resin flow having a laminated structure flowing out from each slit plate constituting the laminating apparatus 7 flows out from the outlets 11L, 12L and 13L of the laminating apparatus as shown in FIG. Then, rearrangement is performed in the cross-sectional shapes of 11M, 12M, and 13M shown in FIG. Next, the length in the film width direction of the cross section of the flow path is widened inside the connecting pipe 9 and flows into the base 10, and further widened by the manifold and extruded from the lip of the base 10 into a sheet in a molten state. Then, it is cooled and solidified on the casting drum to obtain an unstretched film. Here, the value obtained by dividing the film width direction length 17 of the base lip, which is the widening ratio inside the base, by the length 15 in the film width direction at the inlet of the base is set to 5 or less, so that lamination by widening is performed. A polarizing reflector, which is a multilayer laminated film that suppresses disturbance and has a uniform reflectance and reflection band in the film width direction, is obtained. More preferably, the widening ratio is 3 or less.

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

  First, the case of sequential biaxial stretching will be described. Here, stretching in the longitudinal direction refers to stretching for imparting molecular orientation in the longitudinal direction to the film, and is usually performed by a difference in peripheral speed of the roll, and this stretching may be performed in one step. Alternatively, a plurality of roll pairs may be used in multiple stages. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for either of the resin which comprises a laminated | multilayer film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +100 degreeC of resin which comprises a laminated | multilayer film are preferable.

  The uniaxially stretched film thus obtained is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then functions such as slipperiness, easy adhesion, and antistatic properties are provided. It may be applied by in-line coating.

  The stretching in the width direction refers to stretching for giving the film an orientation in the width direction. Usually, the tenter is used to convey the film while holding both ends of the film with clips, and the film is stretched in the width direction. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for either of the resin which comprises a laminated | multilayer film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises a laminated | multilayer film are preferable.

  The biaxially stretched film is preferably subjected to a heat treatment at a temperature not lower than the stretching temperature and not higher than the melting point in the tenter in order to impart flatness and dimensional stability. After being heat-treated in this way, it is gradually cooled down uniformly, then cooled to room temperature and wound up. Moreover, you may use a relaxation process etc. together in the case of annealing from heat processing as needed.

  Next, the case of simultaneous biaxial stretching will be described. In the case of simultaneous biaxial stretching, the resulting cast film is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then, such as slipperiness, easy adhesion, antistatic properties, etc. The function may be imparted by in-line coating.

  Next, the cast film is guided to a simultaneous biaxial tenter, and conveyed while holding both ends of the film with clips, and stretched in the longitudinal direction and the width direction simultaneously and / or stepwise. As simultaneous biaxial stretching machines, there are pantograph method, screw method, drive motor method, linear motor method, but it is possible to change the stretching ratio arbitrarily and drive motor method that can perform relaxation treatment at any place or A linear motor system is preferred. Although the stretching magnification varies depending on the type of resin, it is usually preferably 6 to 50 times as the area magnification. When polyethylene terephthalate is used as one of the resins constituting the laminated film, the area magnification is 8 to 30 times. Is particularly preferably used. In particular, in the case of simultaneous biaxial stretching, it is preferable to make the stretching ratios in the longitudinal direction and the width direction the same and to make the stretching speeds substantially equal in order to suppress the in-plane orientation difference. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises a laminated | multilayer film are preferable.

  The film thus biaxially stretched is preferably subsequently subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter in order to impart flatness and dimensional stability. In order to suppress the distribution of the main alignment axis in the width direction during this heat treatment, it is preferable to perform a relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone. After being heat-treated in this way, it is gradually cooled down uniformly, then cooled to room temperature and wound up. Moreover, you may perform a relaxation | loosening process in a longitudinal direction and / or the width direction at the time of annealing from heat processing as needed. Immediately before and / or immediately after entering the heat treatment zone, a relaxation treatment is performed in the longitudinal direction.

  In particular, in the laminated film of the present invention, in order to reduce the heat shrinkage rate, it is preferable to perform the first relaxation treatment under the heat treatment temperature and the second relaxation treatment at 100 ° C. or less as the relaxation treatment after the heat treatment. . In this case, it is possible to effectively relieve the tension state of the film without greatly affecting the optical characteristics, and it is possible to suppress the thermal contraction rate particularly under a temperature condition of 150 ° C. or less. Preferably, the first relaxation treatment is 5% or less, and the first and second relaxation treatments are 10% or less in total. In this case, the thermal shrinkage rate can be reduced in a state where the optical characteristics are maintained without causing unnecessary wrinkles or slack in the film.

  Next, an example of the laminated glass forming process of the obtained laminated film will be described below. A laminated glass cut into a size suitable for glass, a resin film used as an intermediate film represented by polyvinyl butyral on one glass, a cut laminated film, a resin film, and the other glass are placed at 120 ° C Temporary pressure bonding is performed by heating for about 1 hour in an atmosphere. Subsequently, this glass is bonded to hold it for 30 minutes in a pressurized and heated state up to 140 ° C. and 1.5 MPa to obtain a laminated glass.

  The laminated glass thus obtained is highly suitable for heat ray cut glass particularly used for automobiles, trains, buildings and the like because of its high transparency and excellent heat ray cut property.

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) Layer thickness, number of layers, layered structure The layer structure of the film was determined by observation with a transmission electron microscope (TEM) for 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 10000 to 40000 times under the condition of an acceleration voltage of 75 kV, a cross-sectional photograph was taken, the layer configuration, and the thickness of each layer Was measured. In some cases, in order to obtain high contrast, a staining technique using a known RuO ₄ or OsO ₄ was used.

(2) Calculation method of layer thickness The TEM photograph image of about 40,000 times obtained in the item (1) was captured with CanonScanD123U at an image size of 720 dpi. Save the image to a personal computer as a bitmap file (BMP) or compressed image file (JPEG), and then use the image processing software Image-Pro Plus ver.4 (distributor Planetron Co., Ltd.) Was opened and image analysis was performed. 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 data of the position (nm) and the brightness was adopted in the sampling step 6 (decimation 6), and then numerical processing of a three-point moving average was performed. Furthermore, the obtained data whose brightness changes periodically is differentiated, and the maximum and minimum values of the differential curve are read by a VBA (Visual Basic for Applications) program. The layer thickness was calculated as the layer thickness. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated. Of the obtained layer thickness, a layer having a thickness of 1 μm or more was defined as a thick film layer. The thin film layer was a layer having a thickness of 500 nm or less.

(3) Measurement of reflectance / transmittance A sample was cut out at 5 cm × 5 cm from the center in the film width direction. The reflectance and transmittance were measured with a basic configuration using an integrating sphere attached to a spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd. In the reflectance measurement, the measurement was performed using the sub-white plate of aluminum oxide attached to the apparatus as a reference. In the reflectance measurement and the transmittance measurement, the MD (Machine Direction) direction of the sample was set to the vertical direction, the former was placed behind the integrating sphere, and the latter was placed on the holder in front of the integrating sphere. Measurement conditions: slit is 2 nm (visible) / automatic control (infrared), gain is set to 2, and scanning speed is 600 nm / min. The reflectance R and transmittance T at an azimuth angle of 0 to 180 degrees were obtained. In addition, the attached aluminum oxide was used for the sub white board. Moreover, the solar radiation reflectance and visible light transmittance prescribed | regulated by ISO9050 were computed using the value of the obtained reflectance and transmittance.

(4) Calculation of C * value, a * value, and b * value A sample was cut out from the central part in the film width direction at 5 cm × 5 cm, and then the sample was set and measured using CM-3600d manufactured by Konica Minolta Co., Ltd. went. In addition, the measurement average value of 3 times was used. The measurement was performed under the following conditions.

Measuring device: Konica Minolta Sensing Co., Ltd.
White calibration plate: CM-A103
Zero calibration box: CM-A104
Measurement mode: reflection SCI method (including regular reflection light and diffuse reflection light)
Measurement diameter: φ8mm target mask (CM-A106)
Viewing angle: 10 ° viewing field Light source: D65.

(4) Refractive index of thermoplastic resins A and B Measured according to JIS K7142 (1996) A method.

(5) Thermal contraction rate The sample was cut out from the center part of the film width direction to the longitudinal direction 150mm x width direction 10mm. This sample piece was left in an atmosphere of 23 ° C. and 60% RH for 30 minutes, and in that atmosphere, two marks were made at an interval of about 100 mm in the longitudinal direction of the film, and a Nikon universal projector (Model V-16A) was used. ) Was used to measure the interval between the marks, and the value was taken as A. Next, the sample is allowed to stand in an atmosphere of 150 ° C. under a load of 3 g for 30 minutes, and then cooled for 1 hour in an atmosphere of 23 ° C. and 60% RH. This was measured and designated as B. At this time, the thermal contraction rate was calculated from the following formula (8). For each of the film longitudinal direction (MD) and the width direction (TD), the n number was 3, and the average value was adopted.

    Thermal contraction rate (%) = 100 × (A−B) / A (8)

(7) 5% stress According to the method prescribed | regulated to JIS-K7127 (1999), it measured using the Instron type tensile tester. The elongation is set to a high value in either the film longitudinal direction or the width direction. The measurement was performed under the following conditions.

Measuring device: “Tensilon AMF / RTA-100” automatic tensile strength measuring device manufactured by Orientec Co., Ltd.
Sample size: width 10mm x test length 50mm
Pulling speed: 300mm / min
Measurement environment: temperature 100 ° C.

[Example 1]
A thermoplastic resin A and a thermoplastic resin B were prepared as two types of thermoplastic resins having different optical characteristics. As the thermoplastic resin A, polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 was used. This resin A was a crystalline resin, and the in-plane average refractive index after film formation was 1.66. As the thermoplastic resin B, ethylene terephthalate (PE / SPG · T / CHDC) copolymerized with 25 mol% spiroglycol and 30 mol% cyclohexanedicarboxylic acid was used. The intrinsic viscosity of the resin B was an amorphous resin of 0.72, and the in-plane average refractive index after film formation was 1.55. The prepared thermoplastic resins A and B were respectively charged into two single-screw extruders, melted at 280 ° C., and kneaded. Next, after passing through five FSS type leaf disk filters, each is measured with a gear pump so that the ratio of the optical thickness excluding the thick film layer is thermoplastic resin A / thermoplastic resin B = 1. On the other hand, a 601-layer laminating apparatus in which a total of three slit plates with 201 slits were used together was joined to form a laminate in which 601 layers were alternately laminated in the thickness direction. The method for forming a laminate was carried out according to the description in paragraphs [0053] to [0056] of JP-A-2007-307893. Since there are layers formed by overlapping the A layers, the number of gaps in the slit plate is 603. Here, all the slit lengths are constant, and only the slit gap is changed to make the layer thickness distribution an inclined structure. The obtained laminated body was 301 layers of the thermoplastic resin A and 300 layers of the thermoplastic resin B, and had an inclined structure laminated alternately in the thickness direction. The target layer thickness distribution pattern calculated from the gap between the slit plates of the laminating apparatus is shown in FIG. The slit gap was adjusted so that the thick film layer had a thickness 20 times that of the adjacent layer. Moreover, the value obtained by dividing the film width direction length 17 of the base lip, which is the widening ratio inside the base, by the length 15 in the film width direction at the inlet of the base was set to 2.5.

  The obtained cast film was heated in a roll group set at 75 ° C., and then stretched 3.3 times in the longitudinal direction while rapidly heating from both sides of the film with a radiation heater between 100 mm in the stretch section length, and then temporarily Cooled down. Subsequently, both sides of this uniaxially stretched film were subjected to corona discharge treatment in air, the wetting tension of the base film was set to 55 mN / m, and the treated surface (polyester resin having a glass transition temperature of 18 ° C.) / (Glass transition) Polyester resin having a temperature of 82 ° C.) / Laminate-forming film coating liquid composed of silica particles having an average particle diameter of 100 nm was applied to form a transparent, easy-sliding, and easy-adhesion layer.

  This uniaxially stretched film was guided to a tenter, preheated with hot air at 100 ° C., and then stretched 3.5 times in the transverse direction at a temperature of 110 ° C. The stretched film is directly heat-treated with hot air at 240 ° C. in the tenter, followed by 2% relaxation treatment in the width direction under the same temperature condition, and further 5% relaxation in the width direction after quenching to 100 degrees. After the treatment, a wound laminated film was obtained. The obtained film is provided with about 400 layers of component laminate elements Ln that reflect light of 900 to 1200 nm and about 100 layers of component laminate elements Lv that reflect light of 400 to 700 nm, and has a wavelength of 400 to 700 nm in the visible light region. However, depending on the viewing angle of the transmitted light, a slight change in color was observed. The obtained results are shown in Table 1.

[Example 2]
First, a 401-layer laminated film was formed in the same manner as in Example 1 except that a 401-layer laminating apparatus having a configuration in which two slit plates with 201 slits were used for a film provided with the laminated element Ln was used. Obtained. This laminated film had a layer thickness distribution pattern corresponding to 12 and 13 in FIG. Similarly, a 201-layer laminated film was obtained in the same manner as in Example 1 using a 201-layer laminating apparatus in which a film having the constituent laminated element Lv was configured using one slit plate having the number of slits. This laminated film had a layer thickness distribution pattern corresponding to 11 in FIG. Subsequently, 7 μm of urethane adhesive was applied to the film provided with the constituent laminate element Ln using a die-type dry laminator and laminated with the laminate film corresponding to the constituent laminate element Lv to obtain a laminate film. In the dry lamination, the solvent drying temperature of the adhesive was 60 to 80 degrees, the nip pressure at the time of lamination was 4.0 kg / cm3, and the nip temperature was 80 degrees. The obtained film had a flat reflectance distribution at a wavelength of 400 to 700 nm as in Example 1. However, the variation in reflectance was smaller, and the change in the color was almost changed depending on the viewing angle of the transmitted light. It was a thing which cannot be confirmed. The obtained results are shown in Table 1.

[Example 3]
Other than using polyethylene terephthalate (CHDM copolymerized PET) obtained by copolymerizing 30 mol% of cyclohexanedimethanol with respect to 70 mol% of ethylene glycol as a film having a constituent laminate element [PETG GN001 made by Eastman] as the thermoplastic resin B ′. Obtained a laminated film in the same manner as in Example 2, and the CHDM copolymerized PET used here had an in-plane average refractive index of 1.575 after being formed into a film. The obtained film had a lower reflectance at a wavelength of 400 to 700 nm than that of Example 2, and the heat ray cutting performance predicted from the spectral characteristics was slightly inferior. The results are shown in Table 1.

[Example 4]
A laminated film was obtained in the same manner as in Example 2 except that a 401-layer laminating apparatus having two slit plates with 201 slits was used as the film having the constituent laminated element Lv. The obtained film had a smaller variation in reflectance at a wavelength of 400 to 700 nm than in Example 2, and the difference in color at the viewing angle was suppressed. The results are shown in Table 1.

[Example 5]
A laminated film was obtained in the same manner as in Example 1 except that the relaxation treatment after the heat treatment was only applied 5% in the width direction at the heat treatment temperature. The obtained film was optically inferior to Example 1 but had a slightly higher heat shrinkage rate. The results are shown in Table 1.

[Example 6]
A laminated film was obtained in the same manner as in Example 1 except that the film including the constituent laminated element Ln was changed to the following laminating apparatus and laminating conditions. The used laminating apparatus is a 401-layer laminating apparatus that uses two slit plates with 201 slits as a film having the constituent laminating element Ln, and the optical thickness ratio excluding the thick film layer of the film is Thermoplastic resin B / thermoplastic resin A = 1.3. The obtained film had a strong reflection band between wavelengths of 400 to 600 nm and was slightly colored even when viewed from the front. However, the a * value and b * value at the viewing angle were There was no change in the sign, and there was little change in color according to the viewing angle. The results are shown in Table 1.

[Example 7]
A laminated film was obtained in the same manner as in Example 6 except that the ratio of the optical thickness excluding the thick film layer was thermoplastic resin B / thermoplastic resin A = 1.6. Although the obtained film was confirmed to be more markedly colored even when compared with Example 6, it was hardly changed by the viewing angle. The results are shown in Table 1.

[Example 8]
The layer thickness distribution was adjusted so that the average reflectance at a reflection wavelength of 400 nm to 600 nm was about 20% and the average reflectance at a wavelength of 600 to 800 nm was about 40% as a film having the constituent laminated element Lv. A laminated film was obtained in the same manner as in Example 2 except that the layer laminating apparatus was used. Although the obtained film had a remarkable color, the change in the color at the viewing angle was small. The results are shown in Table 1.

[Example 9]
A laminated film was obtained in the same manner as in Example 4 except that polyethylene terephthalate (CHDM copolymerized PET) obtained by copolymerizing 30 mol% of cyclohexanedimethanol with ethylene glycol was used as the thermoplastic resin B [PETG GN001 made by Eastman]. Further, the obtained film exhibited the same optical performance as that of Example 2, but the variation in reflectance at a wavelength of 400 to 700 nm was smaller and the coloration was suppressed. The results are shown in Table 1.

[Example 10]
As shown in FIG. 3, a 1801 layer laminating apparatus having a structure using six slit plates with 301 slits capable of providing a layer thickness distribution as shown in FIG. A laminated film was obtained in the same manner as in Example 1 except that the layer thickness ratio of the layer made of the thermoplastic resin B (B layer) was 1: 5: 1: 1: 5: 1. Although the obtained laminated film was slightly colored, it exhibited very high heat ray cutting performance. The results are shown in Table 1.

[Comparative Example 1]
A laminated film was obtained in the same manner as in Example 6 except that the ratio of the optical thickness excluding the thick film layer was thermoplastic resin B / thermoplastic resin A = 1. The results are shown in Table 1.

  The present invention relates to a heat ray cut film capable of cutting heat rays caused by sunlight or the like. More specifically, the present invention relates to a heat ray cut film that can cut heat rays with high efficiency while maintaining the transparency of transmitted light, and is suitable as a window glass for automobiles, trains, buildings, and the like.

7: Laminating apparatus 71: Slit plate 72: Slit plate 73: Slit plate 8: Merger 9: Connection pipe 10: Base 11: Slope structure of layer thickness formed by slit plate 71 12: Formed by slit plate 72 Layer thickness inclined structure 13: Layer thickness inclined structure formed by slit plate 73 11L: Resin flow path from outlet of slit plate 71 12L: Resin flow path from outlet of slit plate 72 13L: Slit plate 73 Resin channel 11M from the outlet of the resin: The resin channel 12M communicated with the outlet of the slit plate 71 and disposed by the recombiner 12M: The resin flow disposed by the merger communicated with the outlet of the slit plate 72 Path 13M: communicates with the outlet of the slit plate 73 and is arranged by a merger Resin flow path 14: Length in the width direction of the resin flow path 15: Length in the film width direction at the inlet of the base 16: Cross section of the flow path at the inlet of the base 17: Length in the film width of the base lip 18: Layer arrangement order 19: Layer thickness 20: Point indicating thickness of thick film layer 21: Layer thickness distribution of resin A 22: Layer thickness distribution of resin B

Claims (12)

It includes a configuration in which 50 or more layers of two or more thermoplastic resins having different optical properties are alternately laminated, and an average reflectance at a wavelength of 400 to 700 nm is 20% or more and less than 40%, and a wavelength of 900 A laminated film having an average reflectance at ˜1200 nm of 70% or more. 2. The laminated film according to claim 1, wherein a difference between a maximum reflectance and a minimum reflectance at 100 nm continuous within a wavelength of 400 to 700 nm of the laminated film is less than 10%. The C * value of the transmitted light is 5 or more, and the signs of the a * value and the b * value at the incident angle of 0 ° and the incident angle of 45 ° are the same, respectively. Laminated film. The laminated film according to any one of claims 1 to 3, wherein a heat shrinkage rate when heated at 140 ° C for 30 minutes is ± 1% or less. The laminated film according to claim 1, wherein at 140 ° C., a 5% stress during stretching is 10 MPa or less. The solar radiation reflectance is 40% or more, and the laminated film according to any one of claims 1 to 5. Constituent laminated element Ln in which two or more kinds of thermoplastic resins having different optical properties that reflect light having a wavelength of 900 to 1200 nm are alternately laminated, and different optical properties that reflect light having a wavelength of 400 to 700 nm A structural laminated element Lv in which two or more kinds of thermoplastic resins are alternately laminated, and the number of thermoplastic resins in the structural laminated element Ln is greater than the number of thermoplastic resins in the structural laminated element Lv. The laminated film according to any one of claims 1 to 6. The laminated film includes at least one component laminated element (Ln) that reflects light having a wavelength of 900 to 1200 nm, and includes at least one component laminated element (Lv) that reflects light having a wavelength of 400 to 700 nm. 8. The laminate according to claim 7, wherein the in-plane average refractive index difference of each layer constituting the laminated element Ln is 0.01 or more larger than the in-plane average refractive index difference of each layer constituting the constituent laminated element Lv. the film. The laminated film according to claim 7 or 8, wherein an adhesive layer is present between the constituent laminated element Ln and the constituent laminated element Lv. A layer (A layer) made of thermoplastic resin A and a layer (B layer) made of thermoplastic resin B having optical properties different from those of thermoplastic resin A are alternately laminated, and said A layer and B layer The layer thickness coefficient X is 5 or more and 6 or less, or 8 or more and 9 or less. The laminated film according to claim 1, which is characterized by: The longest reflection wavelength is a wavelength of 1200 to 2000 nm. The laminated film according to claim 10. The window glass for motor vehicles provided with the laminated | multilayer film in any one of Claims 1-11.

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