JP6225495B2 - Multilayer laminated film and glass window member using the same - Google Patents

Description

  The present invention relates to a laminated film and a glass window member using the same.

  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 is contained in an intermediate film used in glass or laminated glass, and the heat ray is blocked by the heat ray absorbing material (for example, Patent Document 1), a metal film What is formed on the glass surface by sputtering or the like to reflect and block heat rays (for example, Patent Document 2) A polymer multilayer laminated film in which polymers having different refractive indexes are alternately laminated is inserted between the glass and the intermediate film. There is one that reflects and blocks heat rays (for example, Patent Document 3). Among these, the method using the heat ray absorbing material has a problem that the sunlight is radiated into the room to reduce the heat ray cutting efficiency because sunlight incident from the outside is converted into heat energy. In addition, the glass temperature rises by absorbing heat rays, and the glass body may be damaged due to the difference from the outside air temperature. In addition, in the method of forming a metal film on the glass surface by sputtering or the like, not only heat rays but also visible light is reflected so that it is easy to be colored, and in order to shield electromagnetic waves, communication equipment or the like may not be used internally. .

  On the other hand, the polymer multilayer laminated film can control the layer thickness and select the wavelength to reflect, so it can selectively reflect the light in the near infrared region, cut the heat ray while maintaining the visible light transmittance 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.

  Here, in many cases, a stretched film stretched in at least one direction is generally used as the polymer multilayer laminated film. However, in the case of adding a heat-absorbing material into an interlayer film, which often uses an unstretched film, or in the case of sputtering a metal film on glass, the retardation is low in a stretched film. The rate may be different in three directions perpendicular to the width direction, the length direction, and the thickness direction of the film, and the retardation may be increased. When the retardation of the film is in a specific range, the visibility is not affected under natural light (non-polarized light), but when viewed through a polarizer such as polarized sunglasses, there is a problem that the interference color is visible. For this reason, in an automotive application that is considered as one of the main applications of the heat ray cut glass, there is a case where the driver feels stress due to the interference color by wearing polarized sunglasses during driving. Further, even in the case of window glass for buildings, there are cases in which interference fringes are visible and are not particularly suitable for applications where visibility is required.

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

  In view of the above-described problems of the prior art, an object of the present invention is to provide a laminated film in which interference color is difficult to be observed even when viewed through a polarizer, and a glass window member using the laminated film. .

  In order to solve the problem, the present invention is a laminated film used in combination with a glass member, and the laminated film is formed by alternately laminating 50 or more layers of two or more thermoplastic resins having different optical properties. The average reflectance in the wavelength band of 900 to 1200 nm is 70% or more, and the average reflectance in the wavelength range of 450 nm to 700 nm is 20% or less, and is incident on the film surface. The purpose of the present invention is a laminated film characterized by having a retardation of 0 nm or more and 400 nm or less when a light beam having an angle of 0 ° and a wavelength of 590 nm is incident.

  According to the present invention, even when a light beam from a light source such as sunlight or a fluorescent lamp is viewed through a polarizer, the interference film is suppressed and the laminated film having good visibility and the laminated film are used. A glass window member can be obtained.

  Embodiments of the present invention will be described below, but the present invention is not construed as being limited to the embodiments including the following examples, and can achieve the object of the invention and depart from the gist of the invention. Various changes within the range not to be made are naturally possible. In addition, for the purpose of simplifying the explanation, some explanations will be made by taking an example of a laminated film in which two types of thermoplastic resins having different optical properties are alternately laminated, but three or more types of thermoplastic resins are used. Should be understood in the same way.

  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 two or more thermoplastic resins having 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 any of two orthogonal directions arbitrarily selected in the plane and a direction selected from the 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. If each layer is expressed as an A layer and a B layer, the layers are stacked in a regular arrangement such as A (BA) n (n is a natural number). Thus, by alternately laminating resins having different optical properties, it becomes possible to reflect light of a specific wavelength specified by the relationship between the refractive index difference of each layer and the layer thickness. Further, when the number of layers to be stacked is less than 50, high reflectance cannot be obtained over a sufficient band in the infrared region, and sufficient heat ray cutting performance cannot be obtained. Preferably, each is 400 layers or more, More preferably, each 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. In addition to causing a process failure in the process of forming a laminated glass, the retardation proportional to the film thickness can be increased, so that practically, about 1000 layers are practically used.

  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. Sunlight has an intensity distribution mainly in the visible light region, and the intensity distribution tends to decrease as the wavelength increases. However, for use in applications where high transparency is required, high heat rays can be obtained by efficiently reflecting light having a wavelength of 900 to 1200 nm (approximately 18% of the intensity of total sunlight) slightly larger than the visible light region. Cut performance can be imparted. 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. Since such a film can be realized by increasing the difference in the in-plane refractive index of two or more kinds of resins having different optical characteristics, a biaxially stretched film is made of a resin made of a crystalline thermoplastic resin. And a laminated film obtained by alternately laminating layers made of a thermoplastic resin that retains amorphous properties during stretching or is melted in a heat treatment step.

  Similarly, the glass window member of the present invention is formed by laminating at least one glass member and at least the laminated film described as the present invention. In the glass window member of the present invention, the glass window member In at least one of the surfaces, the average reflectance in the wavelength band of 900 to 1200 nm needs to be 60% or more. More preferably, the average reflectance in the band of wavelengths 900 to 1200 nm on both surfaces of the glass window member is 60% or more. Moreover, it is desirable that the average reflectance in a wavelength band of 900 to 1200 nm is 70% or more on at least one surface of the glass window member. In the former case, high heat ray cutting performance can be imparted on any surface of the glass window member. In the latter case, high heat ray cutting performance can be imparted. As described above, in order that the average reflectance in the band of the wavelength 900 to 1200 nm is 60% or more on at least one surface of the glass window member, the wavelength 900 to 1200 nm is on at least one surface of the glass window member in the laminated film. It is necessary that the average reflectance in this band is 70% or more. In addition, the laminated film is laminated on the glass surface, and the lamination may be performed via an adhesive, and another layer such as an impact absorbing layer is provided between the glass member and the laminated film. It doesn't matter. In the glass window member of the present invention, which is intended to cut heat rays from the outside, on the other hand, it is possible to suppress reflection on the laminated film by making the laminated film the surface. In some cases, it may be a problem in terms of weather resistance and durability. In that case, it is also preferable to provide a member having little absorption at a wavelength of 900 to 1200 nm outside, and in that case, the light transmittance of the member is preferably 85% or more. When such a member is used, light reflected by the laminated film can be reflected to the outside with almost no absorption, and thus light can be efficiently reflected.

  In the laminated film of the present invention, the average reflectance at a wavelength of 450 to 700 nm needs to be 20% or less. When there is reflection in a wavelength band of 450 to 700 nm, the reflected light or transmitted light is colored, so that there is a possibility that it cannot be applied particularly in applications requiring high transparency such as a windshield of an automobile. When the average reflectance at a wavelength of 450 to 700 nm is 20% or less, coloring of reflected light and transmitted light associated with reflection of visible light can be suppressed, and the film is suitable for applications requiring high transparency. is there. The average reflectance at a wavelength of 400 to 700 nm is preferably 15% or less, more preferably 10% or less. As the average reflectance at a wavelength of 400 to 700 nm is lowered, a highly transparent film can be obtained. In such a film, the ratio of the optical thickness (layer thickness × refractive index) of the layers made of two adjacent two types of thermoplastic resins is controlled to 1 with high accuracy, or the surface is subjected to AR (antireflection) treatment. It can be obtained by applying.

  Similarly, also in the glass window member of the present invention, the average reflectance at a wavelength of 450 to 700 nm needs to be 20% or less as described above. This needs to be satisfied on either side of the glass window member made of glass and film, and when either one is not satisfied, the transmitted light is colored. The average reflectance at a wavelength of 400 to 700 nm is preferably 15% or less, more preferably 10% or less. A glass window member with high transparency comes to be obtained, so that the average reflectance in wavelength 400-700nm falls.

  In the laminated film of the present invention, it is necessary that the retardation is 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident on the film surface at an incident angle of 0 °. Here, the retardation of 0 nm or more and 400 nm or less means that the retardation measured in a range of 3.5 cm square at any location of the film is 0 nm or more and 400 nm or less. When the retardation is 0 nm or more and 400 nm or less through a film having a retardation through a polarizer that strongly transmits one polarization of incident light and shields the other polarization like a polarizing plate, it is viewed through the polarizer. However, it becomes easy to obtain a laminated film in which the interference color is hardly observed. Retardation is defined by the refractive index anisotropy (birefringence) in each layer, the thickness of each layer, and the orientation of each layer. Here, in the stretched film represented by the laminated film of the present invention, the thermoplastic resin A and the thermoplastic resin B generally tend to be oriented in the same direction at the time of stretching, so the birefringence of the layer made of the thermoplastic resin A The product of the sum of the ratio and the layer thickness and the sum of the sub-refractive index and the layer thickness of the layer made of the thermoplastic resin B. From this, in order for retardation at a wavelength of 590 nm at an incident angle of 0 ° to be 0 nm or more and 400 nm or less, it is necessary to suppress the birefringence in each resin. The orientation state of the thermoplastic resin A and the thermoplastic resin is controlled according to the film forming conditions, or one thermoplastic resin is replaced with an amorphous resin, or completely melted to be in the same state as the amorphous resin. Is achieved.

  In the laminated film of the present invention, the retardation obtained when a light beam having a wavelength of 590 nm is incident on the film surface at an incident angle of 0 ° at a position 10 cm inside from the end in the width direction and a center position in the width direction. Is preferably 0 nm or more and 400 nm or less. In addition, when the width direction of the film cannot be specified, the retardation is 0 nm or more and 400 nm at a position 10 cm inside from both the upper, lower, left, and right sides and a central position thereof. In such a case, since it becomes easy to obtain a laminated film in which interference color is hardly observed at any part of the film through a polarizer, particularly when used for a glass window member having a large area. In this case, a high-quality glass window member having no interference color can be obtained. In order to obtain such a laminated film, it is achieved by adjusting the transverse stretching step and the heat treatment conditions as described later.

  In the laminated film of the present invention, it is also preferable that the difference in the orientation angle at a location 10 cm inside from the end in the width direction is ± 30 ° or less with respect to the orientation angle at the location in the center of the film. The orientation angle as used herein refers to the direction in which the refractive index is the largest in the film plane when the width direction of the film is 0 °. When the width direction of the film cannot be specified, the orientation angle is measured based on the arbitrarily set direction at the center portion of the portion 10 cm inside from both the upper, lower, left and right sides, and from both the upper, lower, left and right sides. The difference between the orientation angle at the position 10 cm inside and the orientation angle at the center position is ± 20 ° or less. The degree of coloring seen through the polarizer is determined by the retardation of the film and the orientation angle relative to the polarizer. Here, depending on the value of retardation, the intensity of transmitted light may change due to variations in the orientation angle in the film plane, which may be observed as unevenness in color or brightness. Therefore, if the difference in orientation angle is 20 ° or less, it is possible to suppress variations in color and brightness within the film plane, and even when viewed through a polarizer in any part of the film. It becomes possible to make this sample. The difference in orientation angle is preferably 15 ° or less, and more preferably 10 ° or less. As the difference in the orientation angle becomes smaller, the interference color and brightness variations when viewed through the polarizer are less visible.

  In the laminated film of the present invention, the retardation when a light beam having a wavelength of 590 nm is incident on the film surface after heating at 150 ° C. for 1 hour at an incident angle of 0 ° is preferably 0 nm or more and 400 nm or less. Some glass window members may require processing under a high temperature condition of 100 ° C. or higher. In that case, even if the retardation of the laminated film is 0 nm or more and 400 nm or less, the retardation value may change and become larger than 400 nm in the processing step. Therefore, the laminated film of the present invention was heated at 150 ° C. for 1 hour. It is desirable that the retardation is 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident on the subsequent film surface at an incident angle of 0 °. By doing so, even when processing under a high temperature condition is required, it becomes possible to obtain a laminated film in which interference color is difficult to be observed even when viewed through a polarizer.

  Examples of the thermoplastic resin used in the present invention include chain polyolefins such as polyethylene, polypropylene, poly (4-methylpentene-1) and polyacetal, ring-opening metathesis polymerization of norbornenes, addition polymerization, and addition 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, poly Vinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglycolic acid, polystyrene, styrene copolymer polymethyl methacrylate, polycarbonate, polypropylene terephthalate, polyethylene Polyester such as terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polyethersulfone, polyetheretherketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluoroethylene resin, 3 A fluoroethylene 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 aliphatic dicarboxylic acid and a diol or an ester-forming derivative thereof. 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, it is preferable that the difference in the in-plane average refractive index of layers composed of adjacent thermoplastic resins having different optical properties 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 or a mixture of an amorphous thermoplastic resin and a crystalline thermoplastic resin. 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, the absolute value of the difference in SP value (also referred to as a solubility parameter) of each thermoplastic resin is 1.0 or less. First of all, it is preferable. When the absolute value of the SP value difference is 1.0 or less, delamination hardly occurs, and it is advantageous in increasing the lamination accuracy. More preferably, the polymers having different optical properties preferably contain the same repeating unit. For example, when polyethylene terephthalate is used as one thermoplastic resin, it is preferable to include an ethylene terephthalate unit from the viewpoint of easily realizing a highly accurate laminated structure.

  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 difference in glass transition temperature is larger than 20 ° C., the thickness uniformity when the laminated film is formed becomes poor, which causes variations in the heat ray cutting performance. Also, when a laminated film is formed, problems such as overstretching tend to occur. Further, the retardation of the present invention is the product of the sum of the birefringence and the layer thickness of the layer made of the thermoplastic resin A and the sum of the sub-refractive index and the layer thickness of the layer made of the thermoplastic resin B as described above. Therefore, it becomes important for the retardation to be uniform by suppressing unevenness in the thickness of the film.

  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 comprises polyethylene terephthalate or polyethylene naphthalate, and at least one thermoplastic resin is spiroglycol carboxylate. It is preferable that it is a polyester comprising units. The polyester comprising spiroglycol carboxylate units refers to a copolyester copolymerized with spiroglycol, a homopolyester, or a polyester blended with them. Polyesters containing spiroglycol carboxylate units are preferred because they have a small glass transition temperature difference from polyethylene terephthalate or polyethylene naphthalate, and are therefore less likely to be overstretched during molding and 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 obtained using spiroglycol and cyclohexanedicarboxylic acid. In the case of a polyester obtained by using 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, at least one thermoplastic resin contains polyethylene terephthalate or polyethylene naphthalate, and even in a single composition, a small amount of other repeating units are copolymerized, or a small amount of Other polyester resins may be blended, and at least one thermoplastic resin is preferably a polyester comprising cyclohexanedimethanolcarboxylate units. The polyester comprising a cyclohexanedimethanol carboxylate unit refers to a copolyester obtained by copolymerizing cyclohexanedimethanol, a homopolyester, or a polyester obtained by blending them. Polyesters comprising cyclohexanedimethanol carboxylate units are preferred because they have a small glass transition temperature difference from polyethylene terephthalate or polyethylene naphthalate, and are therefore less likely to be overstretched during molding and 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, it is preferable that only one melting point is observed in differential scanning calorimetry. This indicates that one thermoplastic resin is crystalline and the other thermoplastic resin is in an amorphous state. Thus, if the other thermoplastic resin is in an amorphous state, the birefringence of the layer made of the thermoplastic resin in the amorphous state can be greatly suppressed, and the incident angle is 0 ° with respect to the film surface. Thus, it becomes easy for the retardation when a light beam having a wavelength of 590 nm is incident to be from 0 nm to 400 nm.

  In the laminated film of the present invention, among the thermoplastic resins constituting the laminated film, at least one resin is a crystalline polyester resin, and at least one of the remaining thermoplastic resins is an amorphous polyester resin. Preferably there is. The crystallinity here means that the heat of fusion is 5 J / g or more in differential scanning calorimetry (DSC). On the other hand, “amorphous” means that the heat of fusion is similarly less than 5 J / g. The crystalline polyester resin can have an in-plane refractive index higher than that in an amorphous state before stretching by orientation crystallization in the stretching / heat treatment step. On the other hand, in the case of an amorphous polyester resin, by performing the heat treatment at a temperature far exceeding the glass transition temperature in the heat treatment step, it is possible to completely relieve some of the orientation that occurs in the drawing step, and the low refractive index in the amorphous state. The rate can be maintained. Thus, since the refractive index difference can be easily provided between the crystalline polyester resin and the amorphous polyester resin in the stretching and heat treatment steps in the production of the film, the average reflection at a wavelength of 900 to 1200 nm as described later. In addition to being able to increase the rate, it becomes easy to set the retardation to 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident on the film surface at an incident angle of 0 °. More preferably, the heat of fusion in the differential scanning calorimetry (DSC) of the crystalline polyester is preferably 20 J / g or more. In this case, since orientational crystallization can be more strongly performed in the stretching / heat treatment step, a refractive index difference from the amorphous resin polyester resin can be easily provided.

  In the laminated film of the present invention, among the thermoplastic resins constituting the laminated film, at least one resin is a crystalline polyester resin, and at least one of the remaining thermoplastic resins is the crystalline polyester resin. It is also preferable that the polyester resin has a melting point 30 ° C. lower than the melting point of the polyester resin. When the difference between the melting points of the two crystalline polyester resins is 30 ° C or higher, heat treatment is performed at a temperature between the melting points of the two crystalline polyester resins to melt or amorphize the low-melting polyester resin. As a result, it becomes possible to provide a difference in refractive index between the two types of polyester resins. As a result, in addition to being able to increase the average reflectance at a wavelength of 900 to 1200 nm, the retardation at a wavelength of 590 nm at an incident angle of 0 ° with respect to the film surface can be easily set to 0 nm or more and 400 nm or less. Become.

  In the laminated film of the present invention, the thickness unevenness in the film width direction and the longitudinal direction is preferably 5% or less. The thickness unevenness here is a value obtained by measuring the total length in the width direction and the longitudinal direction of the obtained film, but in the case of a roll-shaped film, it is obtained by measuring at a measurement length of 2000 mm. The retardation is a product of the sum of the birefringence and layer thickness of the layer made of the thermoplastic resin A and the sum of the sub-refractive index and layer thickness of the layer made of the thermoplastic resin B as described above. Therefore, variation in retardation can be suppressed by suppressing uneven thickness of the film. In order to make the thickness unevenness in the film width direction and the flow direction 5% or less, it can be achieved by controlling the glass transition temperature of the thermoplastic resin as described above or by the film forming conditions described later.

  In the laminated film of the present invention, the difference in Young's modulus between the longitudinal direction and the width direction of the laminated film is preferably 0.2 GPa or less. Thus, by setting the difference in Young's modulus of the laminated film to 0.2 GPa or less, the retardation when a light beam having a wavelength of 590 nm is incident on the film surface of the original laminated film at an incident angle of 0 ° is from 0 nm to 400 nm. In addition to facilitating the following, when an external force is applied to the laminated film in various processing steps, anisotropy is hardly generated in the orientation state, and the retardation is maintained at 0 nm or more and 400 nm or less after the processing step. Is easy. In order to obtain such a laminated film, it is possible to appropriately adjust the film forming conditions.

  Next, a preferred method for producing the laminated film of the present invention will be described below with reference to an example using two types of thermoplastic resins, thermoplastic resin A and thermoplastic resin B. Of course, the present invention is not construed as being limited to such examples. In addition, the formation of the laminated structure of the laminated film can be realized by referring to the descriptions in [0053] to [0063] stages of JP-A No. 2007-307893.

  A thermoplastic resin is 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. These resins are formed into a desired shape by a die and then discharged. And the sheet | seat laminated | stacked in the multilayer discharged | emitted from die | dye is extruded on cooling bodies, such as a casting drum, and is cooled and solidified, and a casting film is obtained. At this time, it is preferable to use a wire-like, tape-like, needle-like, or knife-like electrode to be brought into close contact with a cooling body such as a casting drum by an electrostatic force and rapidly solidify. Also preferred is a method in which air is blown out from a slit-like, spot-like, or planar device to be brought into close contact with a cooling body such as a casting drum and rapidly cooled and solidified, or brought into close contact with a cooling body with a nip roll and rapidly solidified.

  Moreover, when producing the multilayer laminated film which consists of a some thermoplastic resin, several resin is sent out from a different flow path using two or more extruders, and is sent into a multilayer lamination apparatus. As the multi-layer laminating apparatus, a multi-manifold die, a feed block, a static mixer, etc. can be used. In particular, 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 preferable to use the feed block including the above. When such a feed block is used, since the apparatus does not become extremely large, there is little foreign matter due to thermal degradation, and high-precision lamination is possible even when the number of laminations is extremely large. Also, the stacking accuracy in the width direction is significantly improved as compared with the prior art. It is also possible to form an arbitrary layer thickness configuration. In this apparatus, since the thickness of each layer can be adjusted by the shape (length, width) of the slit, any layer thickness can be achieved.

  The molten multilayer laminate formed in the desired layer structure in this way is led to a die, and a casting film is obtained in the same manner as described above.

  The casting film thus obtained is preferably biaxially stretched. Here, 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, simultaneous biaxial stretching is used from the viewpoint of isotropic property of mechanical properties such as Young's modulus, a point capable of suppressing retardation, a retardation in the width direction, and uniformity of orientation angle. preferable.

  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. The stretching ratio varies depending on the type of resin, but usually 2 to 15 times is preferable, and when polyethylene terephthalate is used for any of the resins constituting the multilayer laminated film, 2 to 7 times is particularly preferably used. . Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +100 degreeC of resin which comprises a multilayer laminated film are preferable.

  Here, particularly in the laminated film of the present invention, it is also preferable to strengthen the orientation in the longitudinal stretching. In normal sequential biaxial stretching, the orientation tends to be strong in the film width direction, which causes retardation. Here, by strengthening the orientation in the longitudinal stretching, the orientation state in the film width direction and the flow direction can be adjusted to the same extent, and retardation when a light beam having a wavelength of 590 nm is incident on the film surface at an incident angle of 0 ° is obtained. It becomes easy to set it to 0 nm or more and 400 nm or less. A preferred stretching condition for strengthening the orientation is stretching in the range of a glass transition temperature of -5 ° C to + 5 ° C. For example, when polyethylene terephthalate having a glass transition temperature of about 80 ° C is used, the stretching temperature is 75 to 85 ° C. It is preferable to stretch 3.5 times or more in the range. In this case, not only the retardation can be suppressed, but also the retardation uniformity in the film width direction and the suppression of film thickness unevenness are effective.

  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 the both ends with clips and stretch in the width direction. The stretching ratio varies depending on the type of resin, but usually 2 to 15 times is preferable, and when polyethylene terephthalate is used for any of the resins constituting the multilayer laminated film, 2 to 7 times is particularly preferably used. . Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises a multilayer laminated film are preferable.

  Here, particularly in the laminated film of the present invention, the stretching temperature is lowered stepwise when stretching in the film width direction in order to suppress retardation in the film width direction and to improve the retardation in the film width direction and the uniformity of the orientation angle. It is also preferable to employ a method of raising the temperature from 1 to a high temperature, a method of stretching at a high stretch ratio during stretching in the film width direction, and then stretching at a low stretch ratio. One of the causes of a decrease in retardation and orientation angle uniformity in the width direction is often accompanied by stretching stress acting in the film flow direction during stretching in the width direction. Here, by adopting the above-described method, it is possible to suppress the stress generated in the film flow direction at the time of stretching in the film width direction and relatively increase the stress in the film width direction. And uniform distribution angle.

  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. By performing the heat treatment, the dimensional stability of the molding film is improved. 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.

  Here, in particular, in the laminated film of the present invention, in order to suppress retardation in the film width direction, after stretching in the film width direction, it is also preferable to perform heat treatment after once cooling to the glass transition temperature or lower. In this case, it becomes possible to suppress the stretching stress in the film flow direction in the stretching process in the film width direction by cooling to the glass transition temperature or lower, and as a result, the uniformity of retardation in the film width direction can be improved. is there.

  Moreover, in the laminated | multilayer film of this invention, it is also preferable to raise the temperature at the time of heat processing in steps. More preferably, when the temperature at the end of stretching in the film width direction is T1, the temperature at the start of heat treatment is T2, and the maximum temperature of the heat treatment step is T3, T2 is T1 + 10 ° C. or higher and T3-10 ° C. or lower. More preferably, T2 is in the range of (T1 + T3) / 2 ± 10 ° C. In this way, even by gradually increasing the heat treatment temperature, it becomes possible to suppress the stretching stress in the film flow direction in the stretching process in the film width direction, and as a result, the uniformity of the retardation in the film width direction can be reduced. It can be enhanced.

  In the laminated film of the present invention, it is also preferable that the film is stretched by 1.01 times or more and 1.2 times or less with respect to the film width after the stretching process in the film width direction in the heat treatment process. In the heat treatment step, almost no stress is generated in the longitudinal direction of the film, so that the retardation in the width direction and the uniformity of the orientation angle can be improved. On the other hand, when the draw ratio in the film width direction in the heat treatment step is greater than 1.2 times, the film has uneven thickness, and on the contrary, the retardation may deteriorate.

  In the laminated film of the present invention, the heat treatment temperature after stretching is preferably not higher than the melting point of at least one thermoplastic resin and not lower than at least one melting point of the remaining thermoplastic resin. In this case, one of the thermoplastic resins maintains a high orientation state, while the orientation of the other thermoplastic resin is relaxed, so that the refractive index difference between these resins can be easily provided, and It becomes easy for the retardation to be 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident on the film surface at an incident angle of 0 °.

  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 multilayer laminated film, the area magnification is 8 to 30. Double 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 multilayer laminated 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.

  Next, a method for using the obtained laminated film for a glass window member will be described.

  As an example of the glass window member, a method of attaching the present laminated film to the glass surface of the glass window member can be considered. At this time, an adhesive layer is provided on at least one surface of the laminated film. The adhesive layer is not particularly limited, but it is necessary that the adhesive layer has good adhesiveness to both the base material of the film and the base material used for the glass window member. Further, the base material used for the glass window member is not particularly limited, and may be glass or a hard resin such as polycarbonate or acrylic resin. Although the method for forming the adhesive layer is not particularly limited, depending on the composition of the adhesive layer and the type of solvent used for formation, it is necessary to perform curing and drying under a high temperature condition of 100 ° C. or higher. If the laminated film has a retardation of 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident on the film surface after heating at 150 ° C. for 1 hour, the film surface is processed through a polarizer. It becomes possible to make a glass window member in which the interference color is difficult to be observed. It is also preferable to provide a functional layer such as a surface protective layer, a colored layer, or a heat ray absorbing layer on the other surface that is not bonded to the glass window member.

  As another example of the glass window member, a glass window member in which the laminated film of the present invention is one of the constituent elements of laminated glass can be considered. This is a technique used for safety glass such as a windshield of an automobile. In this case, a particularly preferable configuration is that the laminated film of the present invention is sandwiched between two interlayer films, and further this interlayer film-laminate film. -A structure in which a laminate of intermediate films is sandwiched between two glasses. Even in such a laminated glass process, the laminated film, the intermediate film, and the laminated glass process in which the glass is integrated are often treated at a high temperature condition of 100 ° C. or higher. At that time, the film after heating at 150 ° C. for 1 hour If the laminated film has a retardation of 0 nm or more and 400 nm or less at a wavelength of 590 nm at an incident angle of 0 ° with respect to the surface, a glass window member in which interference color is difficult to be observed even after processing through a polarizer. It becomes possible. The intermediate film and glass used in this configuration are not particularly limited, and if necessary, an intermediate film or glass having other functions such as a heat ray absorbing intermediate film, a sound insulating intermediate film, a heat ray reflecting glass, or a heat ray absorbing glass. It is also preferable to use.

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) Reflectance The reflectance was measured with a basic configuration using an integrating sphere attached to a spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd. as a sample cut out at 5 cm × 5 cm. 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, the sample was placed behind the integrating sphere with the longitudinal direction of the sample in the vertical direction. Measurement conditions: The slit was set to 2 nm (visible) / automatic control (infrared), the gain was set to 2, the scanning speed was measured at 600 nm / min, and the reflectance at an azimuth angle of 0 degree was obtained.

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

(4) Retardation / Orientation Angle A phase difference measuring device (KOBRA-21ADH) manufactured by Oji Scientific Instruments was used. A film sample cut out at 3.5 cm × 3.5 cm was placed in the apparatus, and the retardation at a wavelength of 590 nm at an incident angle of 0 ° was measured. Sampling was performed from a central portion on a film roll having a width of 600 mm and a position 10 cm from one end.

(5) Heat of melting and melting points of thermoplastic resins A and B A sample mass of 5 g was taken from the thermoplastic resins A and B, and a differential scanning calorimeter (DSC) was used using a robot DSC-RDC220 manufactured by Seiko Electronics Industry Co., Ltd. It was measured and calculated according to JIS-K-7122 (1987). In the measurement, the temperature was raised from 25 ° C. to 290 ° C. at 5 ° C./min, and the integral value from the baseline in the range of melting point ± 20 ° C. at this time was defined as the heat of fusion. In addition, the melting point here is the point where the difference from the baseline of DSC is maximized. Here, a resin having a heat of fusion of 20 J / g or more is a crystalline resin, and a resin having a heat of fusion of 5 J / g or less is an amorphous resin.

(6) Thickness unevenness Using a film thickness tester KG601A manufactured by Anritsu Corporation, the film thickness was measured by running 1 m in the width direction and the flow direction of the film at a speed of 3 m / sec. The film thickness was read with a wide-range electronic micrometer K306C manufactured by Anritsu Corporation, and the thickness unevenness was calculated by the following formula. The measurement length was 600 mm in the film width direction and 2000 mm in the longitudinal direction.

Thickness variation (%) = (maximum thickness−minimum thickness) / average thickness × 100
(7) Young's modulus A sample was cut from the center in the width direction of the film at 15 cm in the longitudinal direction and 1.5 cm in the width direction, and used as a sample for measuring Young's modulus in the longitudinal direction. Similarly, a sample for measuring Young's modulus in the width direction was cut out at 15 cm in the width direction and 1.5 cm in the longitudinal direction. Elastic modulus, breaking strength, breaking elongation were measured with a tensile tester (Tensilon UTM-III manufactured by Toyo Sokki Co., Ltd.) with a test length of 10 cm, pulled at a speed of 20 cm / min, and recorded stress-strain curves. And by the method of JIS K 7113.

Hereinafter, Examples 1, 2, and 10-14 shall be read as Reference Examples 1, 2, and 10-14.
Example 1
As two types of thermoplastic resins having different optical characteristics, thermoplastic resin A is polyethylene terephthalate having an intrinsic viscosity of 0.65 and a melting point of 255 ° C. (hereinafter, also referred to as PET. In-plane refractive index in a film after stretching and heat treatment) Was approximately 1.66), and a copolymer of polyethylene terephthalate having an intrinsic viscosity of 0.72 and amorphous (a spiroglycol component of 20 mol%) was used as an amorphous thermoplastic resin B using [Toray F20S]. This is a polymerized PET, which is hereinafter also referred to as SPG copolymerized PET 1. The in-plane refractive index of the film after stretching and heat treatment was 1.550).

  The thermoplastic resin A and the thermoplastic resin B thus prepared were each melted at 280 ° C. with a vented twin-screw extruder and then fed into a 401-layer feed block via a gear pump and a filter. Merged. Both the surface layer portions were made of the thermoplastic resin A, and the layer thicknesses of the layer A made of the thermoplastic resin A and the layer B made of the thermoplastic resin B were made substantially the same. Subsequently, after being merged by a 401 layer feed block, led to a T-die and formed into a sheet shape, it was rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. by electrostatic application to obtain a cast film. . The discharge amount was adjusted so that the weight ratio of the thermoplastic resin A and the thermoplastic resin B was about 1: 1 so that the thickness ratio of adjacent layers was about 1.

  The obtained cast film was heated with a roll group set at 75 ° C., and then stretched 3.8 times in the longitudinal direction while rapidly heating from both sides of the film with a radiation heater within a stretching section length of 100 mm. Cooled down. The film temperature during stretching was 85 ° C. 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 of 90 ° C., and stretched 3.8 times at a temperature of 100 ° C. in the transverse direction at a uniform stretching speed. The stretched film was directly heat-treated with hot air at 240 ° C. in the tenter, subsequently subjected to a relaxation treatment of 1% in the width direction at the same temperature, and then gradually cooled to room temperature and wound up.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, the retardation was sufficiently low in the width direction, but the uniformity of the orientation angle was low.

  Subsequently, after an adhesive layer was provided on one surface of the obtained film, it was bonded to glass having a thickness of 2 mm to obtain a glass window member.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. In addition, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloration or the like was observed in any place in the width direction, but there was a slight difference in brightness in the width direction. The results are shown in Table 1.

(Example 2)
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that the longitudinal draw ratio was 3.3 times.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, although the retardation was sufficiently low, the retardation was slightly higher in the vicinity of the end in the width direction than in Example 1, and the uniformity of the orientation angle was also slightly lowered.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. In addition, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloring or the like was confirmed. There was a difference in brightness. The results are shown in Table 1.

(Example 3)
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that stretching was performed at 95 ° C., 100 ° C., and 105 ° C. in three stages and the stretching temperature was increased at the time of transverse stretching.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, compared with Example 1, the retardation was sufficiently low in the width direction, and the uniformity of the orientation angle was also good.

The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, almost no difference in coloration or brightness was observed at any location in the width direction. The results are shown in Table 1.
Example 4
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that stretching was performed at 95 ° C., 100 ° C., and 140 ° C. in three stages and the stretching temperature was increased at the time of transverse stretching.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, even when compared with Example 3, the retardation was sufficiently low in the width direction, and the uniformity of the orientation angle was good.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, almost no difference in coloration or brightness was observed at any location in the width direction. The results are shown in Table 1.

(Example 5)
At the time of transverse stretching, the stretching speed is changed in two stages, the film is stretched 3.0 times in the film width direction in the first 25% section of the stretching section, and stretched to 3.8 times in the remaining 75% section. A laminated film and a glass window member were obtained in the same manner as in Example 1 except that.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, compared with Example 1, the retardation was sufficiently low in the width direction, and the uniformity of the orientation angle was also good.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, almost no difference in coloration or brightness was observed at any location in the width direction. The results are shown in Table 1.

(Example 6)
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that an intermediate cooling zone was provided after transverse stretching and the film temperature was once lowered to 70 ° C.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, compared with Example 1, the retardation was sufficiently low in the width direction, and the uniformity of the orientation angle was also good.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no difference in coloring or brightness was observed at any place in the width direction. The results are shown in Table 1.

(Example 7)
In the heat treatment step, a laminated film and a glass window member were obtained in the same manner as in Example 4 except that the heat treatment temperature in the first 25% section of the heat treatment section was 190 ° C. and the remaining 75% section was 240 ° C.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, compared with Example 4, the retardation and the uniformity of the orientation angle were also good.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no difference in coloring or brightness was observed at any place in the width direction. The results are shown in Table 1.

(Example 8)
Further, in the heat treatment step, a laminated film and a glass window member were obtained in the same manner as in Example 7 except that the film was stretched 1.1 times in the film width direction in the first 25% of the heat treatment section.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. In addition, compared with Example 7, the uniformity of the orientation angle was also better.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no difference in coloring or brightness was observed at any place in the width direction. The results are shown in Table 1.

Example 9
Further, an intermediate cooling zone was provided after transverse stretching, and a laminated film and a glass window member were obtained in the same manner as in Example 1 except that the film temperature was once lowered to 70 ° C.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, the uniformity of the orientation angle was also better than that of Example 8.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no difference in coloring or brightness was observed at any place in the width direction. The results are shown in Table 1.

(Example 10)
As the thermoplastic resin B, a laminated film and a glass window member were prepared in the same manner as in Example 1 except that isophthalic acid copolymerized polycyclohexanedicarboxylic terephthalate (hereinafter also referred to as PCT / I) having a melting point of 210 ° C. and a refractive index of 1.564 was used. Obtained.

  The thickness of the obtained laminated film was 78 μm. Moreover, while maintaining high transparency while reflecting light of 900 to 1200 nm, and having a substantially flat reflectance distribution at a wavelength of 400 to 700 nm in the visible light region, it is slightly 900 to 1200 nm. The reflectivity was low. Further, the retardation was sufficiently low, but the retardation was slightly high around the edge in the width direction.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. In addition, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloring was observed, but on the other hand, there was some coloring at the position corresponding to the periphery of the film width direction end. It was something to be seen. The results are shown in Table 1.

(Example 11)
A laminated film was obtained in the same manner as in Example 1, and the obtained laminated film was laminated in the order of glass, polyethylene vinyl alcohol, laminated film, polyethylene vinyl alcohol, and glass, and then pressure-bonded by an autoclave at 150 ° C. for 1 hour to form a glass window. A member was obtained.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low in the width direction.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloring or the like was confirmed at any place in the width direction. The results are shown in Table 1.

Example 12
Polyethylene terephthalate copolymer that is amorphous with an intrinsic viscosity of 0.72 as thermoplastic resin B (a PET copolymerized with 20 mol% spiroglycol component and 5 mol% butylene glycol component, hereinafter also referred to as SPG copolymerized PET2 (stretched) A laminated film and a glass window member were obtained in the same manner as in Example 1 except that the in-plane refractive index of the heat-treated film was 1.550)).

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low in the width direction.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloring or the like was confirmed at any place in the width direction. The results are shown in Table 1.

(Example 13)
A laminated film was obtained in the same manner as in Example 12, and the obtained laminated film was laminated in the order of glass, polyethylene vinyl alcohol, laminated film, polyethylene vinyl alcohol and glass, and then pressure-bonded by an autoclave at 150 ° C. for 1 hour to form a glass window. A member was obtained.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Moreover, the retardation was sufficiently low in the width direction. On the other hand, the retardation after heating at 150 ° C. for 1 hour was greatly changed.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. On the other hand, the retardation was high, and when the glass window member was viewed through polarized sunglasses, some coloration was observed. The results are shown in Table 1.

(Example 14)
A cast film was obtained in the same manner as in Example 1 using the PET described in Example 1 as the thermoplastic resin A and an acrylic resin having a refractive index of 1.49 as the thermoplastic resin B. Here, the obtained cast film was not subjected to stretching and heat treatment, and after an adhesive layer was provided on one surface, it was bonded to glass having a thickness of 2 mm to form a glass window member.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. However, compared with Example 1, the reflectance of 900-1200 nm was somewhat low. Moreover, the retardation was very low in the width direction.

  The obtained glass window member maintained high transparency while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. Further, the retardation was sufficiently low, and even when the glass window member was viewed through polarized sunglasses, no coloring or the like was confirmed at any place in the width direction. The results are shown in Table 1.

(Comparative Example 1)
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that the longitudinal stretching ratio was 3.3 times and the longitudinal stretching temperature was 90 ° C.

  The thickness of the obtained laminated film was 78 μm. Moreover, it was highly transparent while reflecting light of 900 to 1200 nm, and had a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. However, the retardation was higher than that of Example 1.

  Further, the obtained glass window member retains high transparency while reflecting light of 900 to 1200 nm, and has a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. It was. However, reflecting the height of the retardation, the glass window member was slightly colored through the polarized sunglasses. The results are shown in Table 1.

(Comparative Example 2)
Laminated as in Example 1 except that the thermoplastic resin B is cyclohexanedimethanol copolymerized PET (hereinafter also referred to as CHDM copolymerized PET, and the in-plane refractive index of the stretched and heat-treated film was 1.575). Films and glass window members were obtained.

  The thickness of the obtained laminated film was 78 μm. Further, while reflecting light of 900 to 1200 nm, it maintains high transparency and has a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region, but it reflects at 900 to 1200 nm. The rate was low.

  Further, the obtained glass window member retains high transparency while reflecting light of 900 to 1200 nm, and has a substantially flat reflectance distribution at wavelengths of 400 to 700 nm in the visible light region. However, the reflectance in 900-1200 nm was low, and the heat ray cutting performance was poor. The results are shown in Table 1.

(Comparative Example 3)
A laminated film and a glass window member were obtained in the same manner as in Example 1 except that the discharge amount was adjusted so that the weight ratio of the thermoplastic resin A and the thermoplastic resin B was 0.7: 1.

  The thickness of the obtained laminated film was 78 μm. In addition, the average reflectance at 900 to 1200 nm is slightly lower than that of Example 1, while the film appears to be colored by the reflection peak being seen at a wavelength of 400 to 700 nm in the visible light region. It was.

  Also, the obtained glass window member was colored similarly to the film and was not suitable for use as a glass member. The results are shown in Table 1.

  The laminated film and glass window member of the present invention are particularly used for glass window members of automobiles, trains, buildings and the like.

Claims (8)

A laminated film used in combination with a glass member, wherein the laminated film has a constitution in which 50 or more layers of two or more thermoplastic resins having different optical properties are alternately laminated, and has a wavelength of 900 to 1200 nm. The average reflectance in the band of 70 nm or more and the average reflectance in the band of wavelengths 450 nm or more and 700 nm or less are 20% or less, and light rays with an incident angle of 0 ° and a wavelength of 590 nm are incident on the film surface. and Ri retardation der than 400nm or less 0nm of time, the relative orientation angle in the film central portion of the laminated film, the difference is ± 23 ° of the orientation angle at locations entering the 10cm inward from the end portion in the width direction biaxially oriented laminated film characterized der Rukoto below. Retardation is 0 nm or more and 400 nm or less when a light beam having an incident angle of 0 ° and a wavelength of 590 nm is incident on the film surface at a position 10 cm inside from both ends in the width direction of the laminated film and a center position in the width direction. The biaxially stretched laminated film according to claim 1, wherein the biaxially stretched laminated film is provided. 3. The retardation when the laminated film is heated at 150 ° C. for 1 hour and a light beam having an incident angle of 0 ° and a wavelength of 590 nm is incident on the film surface is 0 nm or more and 400 nm or less. The biaxially stretched laminated film described in 1. In the thermoplastic resin, one of thermoplastic resin but a crystalline thermoplastic resin, any of the preceding claims, wherein the other one thermoplastic resin is a noncrystalline thermoplastic resin biaxially oriented laminated film according to either. In the thermoplastic resin, at least one thermoplastic resin is a crystalline polyester resin, and at least one of the remaining thermoplastic resins is 30 ° C. or more lower than the melting point of the amorphous polyester resin or the crystalline polyester resin. The biaxially stretched laminated film according to any one of claims 1 to 4, which is a crystalline polyester resin having a melting point. The laminated film has a length of 600 nm in the film width direction and a length of 2000 mm or more in the longitudinal direction, and thickness unevenness in the film width direction and the longitudinal direction is 5% or less . The biaxially stretched laminated film described in 1. The biaxially stretched laminated film according to any one of claims 1 to 6, wherein a difference in Young's modulus between the longitudinal direction and the width direction of the laminated film is 0.2 GPa or less. A glass window member formed by laminating at least one glass member and at least one biaxially stretched laminated film according to any one of claims 1 to 7 , wherein one surface of the glass window member The average reflectance in the wavelength band of 900 to 1200 nm is 60% or more, the average reflectance in the wavelength range of 450 nm to 700 nm is 20% or less, and the incident angle is 0 ° with respect to the glass window member surface. Biaxial stretching in which a retardation of 0 nm or more and 400 nm or less when a light beam having a wavelength of 590 nm is incident and two or more types of thermoplastic resins having different optical properties are alternately laminated. A glass window member, which is a laminated film.