JP2017206012A - Laminate film and laminated glass for liquid crystal projection using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film giving a good appearance when processed into a laminated glass and giving a head-up display having high transparency and bright display when assembled into a head-up display.SOLUTION: The laminate film comprises A layers made of a crystalline polyester and B layers made of a thermoplastic resin B different from the crystalline polyester, which are alternately layered in total 11 layers or more; and the laminate film has a Young's modulus of 6 GPa or more in a direction of an orientation axis of the laminate film. When the film is heated at a temperature of Tg(h)-20°C for 6 hours, where Tg(h) represents a higher glass transition temperature in a glass transition temperature Tg(A) of the crystalline polyester and a glass transition temperature Tg(B) of the thermoplastic resin B, the laminate film shows a thermal shrinkage of 0.5% or more in the direction of the orientation axis of the laminate film or in a direction orthogonal to the direction of the orientation axis.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film and a laminated glass for liquid crystal projection using the same. More specifically, the present invention relates to a laminated film that has a good appearance when used as a laminated glass and can be used as a head-up display having high transparency and display brightness when used as a head-up display.

  A head-up display is known as a means for directly displaying information in the human visual field. For example, while driving an automobile, information such as the speed of instruments is directly displayed on the windshield as a virtual image in the vehicle, so that the vehicle can be driven without changing the field of view, thereby preventing accidents. Usually, light emitted from a projector such as a small liquid crystal projector is transmitted and reflected by a display unit made of a transparent base material including a half mirror material. The observer acquires information displayed on the display unit, and simultaneously acquires external information such as an outside landscape through the display unit.

  In the head-up display, a high transmittance and a clear display for accurately transmitting the display to the driver are required for safety reasons. Therefore, for example, Patent Document 1 discloses a head-up display using a film having a polarization reflection characteristic that reflects only polarized light irradiated by a liquid crystal projector.

  On the other hand, as one of the configurations of the head-up display, it is also possible to use a laminated glass in which a film having the above-mentioned polarization reflection property is encapsulated in a windshield for displaying information. It is useful to suppress the deterioration of transparency, appearance deterioration, and safety associated with resin deterioration.

JP-T-2006-512622

Patent Document 1 describes that a film using polyethylene naphthalate (PEN) having a glass transition temperature of 122 ° C. is excellent in polarization reflection characteristics. However, because of the high glass transition temperature of PEN, the film described in Patent Document 1 cannot suppress distortion generated in the film when processed into laminated glass or the like performed at around 130 ° C. There existed a subject that the laminated glass with favorable external appearance was not obtained depending on the shape of glass.
Therefore, in view of the above-described problems of the prior art, the present invention provides a head-up display that has a good appearance when used as a laminated glass and has high transparency and brightness when used as a head-up display. It aims at providing the laminated | multilayer film which can be made.

  In order to solve the problem, the present invention is a laminated film in which a layer A made of crystalline polyester and a layer B made of thermoplastic resin B different from the crystalline polyester are alternately laminated in total of 11 layers or more. And the Young's modulus in the orientation axis direction of the laminated film is 6 GPa or more, and the glass transition temperature of the crystalline polyester is Tg (A), which is higher than the glass transition temperature Tg (B) of the thermoplastic resin B. When the glass transition temperature of Tg (h) is Tg (h), the thermal shrinkage rate when heated at Tg (h) -20 ° C. for 6 hours in either the orientation axis direction of the laminated film or the direction orthogonal to the orientation axis direction is A laminated film characterized by being 0.5% or more.

  The laminated film of the present invention has a good appearance when it is made into a laminated glass, and also has high transparency and high display brightness when used as a laminated glass for liquid crystal projection for a head-up display. A head-up display with excellent performance.

It is a schematic diagram showing a polarized light perpendicular | vertical to the entrance plane containing a film orientation axis direction, and a polarized light parallel to the entrance plane containing a film orientation axis direction.

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

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

  Further, the thermoplastic resin B exhibits optical characteristics or thermal characteristics different from the crystalline polyester A used for the A layer. In the present invention, “differing from the thermoplastic resin A” means exhibiting optical characteristics or thermal characteristics different from those of the thermoplastic resin A. In the present invention, the optical property different from that of the thermoplastic resin A means that the refractive index is 0.01 or more in any of two orthogonal directions arbitrarily selected in the plane of the film and a direction perpendicular to the plane. Represents a different thing. In addition, the phrase “showing thermal characteristics different from those of the thermoplastic resin A” means that, in differential scanning calorimetry (DSC), the crystalline polyester A is different in melting point or glass transition temperature by 1 ° C. or more.

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

  In addition, by alternately laminating resins with different thermal properties, it is possible to highly control the orientation state of each layer when manufacturing a biaxially stretched film. Optical properties, mechanical properties, and heat shrinkage properties Can be controlled.

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

  In addition, when the number of layers to be stacked is 10 or less, high reflectivity cannot be obtained in a desired band. Therefore, when used as a head-up display, sufficient reflection performance cannot be obtained, and the liquid crystal projector is used. The information display becomes dark and unsuitable for use. In addition, 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 that reflects light in a desired band can be obtained. Preferably it is 100 layers or more, More preferably, it is 200 layers or more. More preferably, it is 400 layers or more. In addition, although there is no upper limit to the number of layers, as the number of layers increases, the manufacturing cost increases with an increase in the size of the manufacturing apparatus and the handling properties deteriorate due to the increase in film thickness. The layer is within the practical range.

  In the laminated film of the present invention, the Young's modulus in the orientation axis direction of the laminated film needs to be 6 GPa or more. Here, the orientation direction of the laminated film refers to the direction in which the Young's modulus of the film is measured by changing the direction every 10 ° in the film plane and the Young's modulus is maximized. The Young's modulus is an index indicating the force required at the time of initial deformation of the film. By increasing the Young's modulus, force is applied to the laminated film during processing such as punching, cutting, coating, and laminating in the laminated glass process. In this case, it becomes easy to suppress processing defects and performance changes during use. Preferably, the Young's modulus in the orientation axis direction of the laminated film is 8 GPa or more, more preferably 10 GPa or more. As the Young's modulus increases, the laminated film becomes difficult to deform.For example, since the control range of processing conditions during processing such as punching, cutting, coating and laminating widens, not only processing defects can be suppressed, but also obtained. It is also useful to enhance the performance of the products that are produced. In order to increase the Young's modulus, as will be described later, it is achieved by a film production method in addition to the selection of the resin.

  In the case of a single layer or a few layers, if the Young's modulus in the orientation axis direction of the laminated film is 6 GPa or more, the laminated film tends to become brittle due to the strength of the orientation of the resin, and handling properties are In some cases, it decreased. On the other hand, as in the present invention, in the case of a laminated film in which A layer made of crystalline polyester A and B layer made of thermoplastic resin B different from crystalline polyester A are alternately laminated, a total of 11 layers or more is used. Increases Young's modulus without impairing handling properties due to interfacial tension at the lamination interface and the buffering effect of the B layer made of the thermoplastic resin B, and thus punching, cutting, coating, laminating, etc. Even when a force is applied to the laminated film during use as a processing step or a functional film, an effect of suppressing deformation can be obtained.

  In the laminated film of the present invention, the ratio of Young's modulus in the direction perpendicular to the orientation axis direction of the laminated film and the same plane (Young's modulus in the orientation axis direction / orthogonal in the same plane as the orientation axis direction). It is also a preferable aspect that the Young's modulus in the direction is 2 or more. Even when an attempt is made to increase the Young's modulus ratio simply by selecting a resin or a film manufacturing method, the laminated film having a uniform Young's modulus in the in-plane direction of the laminated film has a limit in Young's modulus. This is because the Young's modulus depends on the orientation strength of the resin constituting the laminated film, and how strongly the Young's modulus is oriented in the direction in which the Young's modulus is desired to affect the magnitude of the Young's modulus.

  On the other hand, in processing steps such as punching, cutting, coating, and laminating, increasing the Young's modulus in the longitudinal direction of the laminated film is effective for stabilizing the processing step from the viewpoint of continuity. Therefore, by setting the ratio of the Young's modulus in the direction perpendicular to the orientation axis direction of the laminated film in the same plane to 2 or more, the Young's modulus on the orientation axis side can be further increased, and the Young's modulus is maximized. It becomes easy for the Young's modulus in the direction (the orientation axis direction of the laminated film) to be 6 GPa or more. More preferably, the ratio of Young's modulus in the direction of the orientation axis of the laminated film and the direction orthogonal to the same plane is 3 or more. In this case, the Young's modulus in the orientation axis direction of the laminated film can be easily set to 10 GPa or more. It becomes.

  In the laminated film of the present invention, among the glass transition temperature Tg (A) of the crystalline polyester and the glass transition temperature Tg (B) of the thermoplastic resin B, the higher glass transition temperature is Tg (h). In either the orientation axis direction or the direction orthogonal to the orientation axis direction of the laminated film, it is necessary that the thermal shrinkage rate when heated at Tg (h) -20 ° C. for 6 hours is 0.5% or more. . The glass transition temperature is determined by DSC in the measurement method described later. When two or more peaks corresponding to the glass transition temperature are confirmed by DSC, the glass transition temperature is measured at the highest temperature among them. The temperature at which the peak top exists is defined as the glass transition temperature. In addition, when only one peak corresponding to the glass transition temperature is observed, the temperature at which the peak top exists is defined as the glass transition temperature. In general, the resin starts micro-Brownian motion at a temperature higher than the glass transition temperature, whereas it becomes difficult to be deformed at a temperature lower than the glass transition temperature due to the glass state. For this reason, even when a film is used, no major deformation occurs below the highest glass transition temperature among the resins constituting the film. On the other hand, polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer, etc., which are generally used in laminated glass, have a glass transition temperature near room temperature, and show softening and shrinkage behavior at a lower temperature compared to films. become. Here, when a film having a glass transition temperature at a high temperature and a polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer having a glass transition temperature at a low temperature are combined to form a laminated glass, the shrinkage start temperature of the film is reduced. There is a problem in that poor appearance results from the difference. Therefore, in either the orientation axis direction of the laminated film or the direction orthogonal to the orientation axis direction, the heat shrinkage rate when heated at Tg (h) -20 ° C. for 6 hours is 0.5% or more, Even when a laminated glass is combined with polyvinyl alcohol, polyvinyl butyral, or ethylene-vinyl alcohol copolymer, the shrinkage start temperature of polyvinyl alcohol, polyvinyl butyral, or ethylene-vinyl alcohol copolymer should be matched with the shrinkage start temperature of the film. And a high-quality laminated glass having no problem in appearance can be obtained. Such a laminated film is achieved by a film production method as described later.

  Preferably, the thermal shrinkage at Tg (h) -20 ° C. is 1.0% or more in either the orientation axis direction or the direction orthogonal to the orientation axis direction of the laminated film, more preferably 2 0.0% or more. By increasing the shrinkage rate, it becomes easier to match the shrinkage start temperature of polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer with the shrinkage start temperature and shrinkage of the film, and processing to make laminated glass Since the selection range of process conditions is broadened and the followability to the shape of a laminated glass having a large curve is improved, it is possible to obtain laminated glass having various shapes and excellent appearance and performance. Moreover, it is also preferable that the thermal contraction rate at Tg (h) -20 ° C. is 5.0% or less in the direction perpendicular to the orientation axis direction of the laminated film. As the thermal shrinkage rate increases, the shape of the laminated glass having a large curve can be easily fitted. On the other hand, there may be a problem that a void at the peripheral edge of the glass is generated due to the shrinkage of the film.

  In the laminated film of the present invention, it is also preferable that the thermal shrinkage rate when heated at 85 ° C. for 6 hours in the orientation axis direction or the direction perpendicular to the orientation axis direction of the laminated film is 0.5% or more. . The shrinkage temperature of polyvinyl alcohol, polyvinyl butyral, and ethylene-vinyl alcohol copolymer is generally 50 to 100 ° C., particularly around 80 to 90 ° C., and by improving the heat shrinkage rate at 85 ° C., Since it becomes easy to match the shrinkage start temperature of polyvinyl butyral and ethylene-vinyl alcohol copolymer with the shrinkage start temperature of the film, a laminated glass excellent in appearance can be obtained. More preferably, it is 1.0% or more. In this case, by increasing the shrinkage rate, it becomes easy to match the shrinkage start temperature of polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer and the shrinkage start temperature of the film, and processing to make laminated glass Since the selection range of process conditions is widened and the followability to the shape of a laminated glass having a large curve is improved, it is possible to obtain laminated glass having various shapes and excellent in appearance and performance.

  In the laminated film of the present invention, the thermal shrinkage rate when heated for 6 hours at Tg (h) -20 ° C. in the orientation axis direction of the laminated film and Tg (h) -20 ° C. in the direction perpendicular to the orientation axis direction. It is also preferable that the difference between the heat shrinkage rate and the heat shrinkage rate when heated for 6 hours is 0.5% or more. Laminated glass for liquid crystal projection is mainly used for windshields, but the windshield has a horizontally long shape, and there are many cases where the vertical and horizontal directions have different curves. At this time, if the difference in thermal shrinkage between the orientation axis direction and the direction perpendicular to the orientation axis direction is small, either the longitudinal or the transverse direction is good due to the difference in the size of the curves of the laminated glass in the vertical and horizontal directions. Although it can be made into a laminated glass shape, an appearance defect may occur on the other side. When the difference in heat shrinkage at Tg (h) -20 ° C. between the orientation axis direction of the laminated film and the direction orthogonal to the orientation axis direction is 0.5% or more, Since the difference in shrinkage behavior corresponding to the difference can be obtained, it becomes easy to obtain a laminated glass excellent in appearance. Preferably, the difference in thermal shrinkage at Tg (h) -20 ° C. between the orientation axis direction and the direction orthogonal to the orientation axis direction is 1.0% or more. In this case, the present invention can also be applied to laminated glass having a larger difference between the vertical and horizontal curves.

  In the laminated film of the present invention, the A layer made of crystalline polyester A is preferably the outermost layer. In this case, since the crystalline polyester A is the outermost layer, a biaxially stretched film can be produced in the same manner as a crystalline polyester film such as a polyethylene terephthalate film or a polyethylene naphthalate film. For example, when the thermoplastic resin B made of an amorphous resin is not the crystalline polyester but is the outermost layer, when obtaining a biaxially stretched film in the same manner as the crystalline polyester film, to production equipment such as rolls and clips There are cases where problems such as film formation failure due to adhesion and surface quality deterioration occur.

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

  Here, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalene. Dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 6,6 '-(ethylenedioxy) di-2-naphthoic acid, 6, Examples include 6 '-(trimethylenedioxy) di-2-naphthoic acid and 6,6'-(butylenedioxy) di-2-naphthoic acid. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, and cyclohexanedicarboxylic acid and ester derivatives thereof. These acid components may be used alone or in combination of two or more.

  In particular, as the carboxylic acid component constituting the crystalline polyester A used in the laminated film of the present invention, a high refractive index is expressed after the maximum stretching, and from the viewpoint of increasing mechanical strength and dimensional stability represented by Young's modulus. Terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferably used. Since terephthalic acid and 2,6-naphthalenedicarboxylic acid contain aromatic rings with high symmetry, it is easy to achieve both high refractive index and excellent mechanical properties by orientation and crystallization. . In particular, when the carboxylic acid component constituting the crystalline polyester A contains 2,6-naphthalenedicarboxylic acid, the volume ratio of the aromatic ring is increased, so that the resin can be produced at low cost and can be melt-formed. It is possible to achieve a high refractive index and excellent mechanical properties.

  In the laminated film of the present invention, the crystalline polyester preferably contains 50 mol% or more of naphthalenedicarboxylic acid among the carboxylic acid components constituting the crystalline polyester. When naphthalenedicarboxylic acid is contained in an amount of 50 mol% or more, orientation and crystallization progress, and it becomes easy to achieve both a high refractive index, a high reflection performance associated therewith, and excellent mechanical properties. Preferably, naphthalenedicarboxylic acid is contained in an amount of 50 mol% to 90 mol%. When the content of naphthalenedicarboxylic acid contained in the carboxylic acid component is 90 mol% or less, the orientation and crystallinity of the crystalline polyester can be controlled, so that it becomes easier to obtain a laminated film suitable for the laminated vitrification process. .

  In addition to the terephthalic acid and 2,6-naphthalenedicarboxylic acid, the carboxylic acid component constituting the crystalline polyester A used in the laminated film of the present invention preferably contains isophthalic acid. By including isophthalic acid, it is possible to control the orientation and crystallinity of the crystalline polyester while maintaining the high polarization reflection performance of the laminated film as compared with the case of only terephthalic acid or 2,6-naphthalenedicarboxylic acid. It becomes easy to obtain a laminated film suitable for the laminated vitrification step.

  Examples of the diol component constituting the crystalline polyester A used in the laminated film of the present invention include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol Mention may be made of ethylene glycol, polyalkylene glycol, 2,2-bis (4-hydroxyethoxyphenyl) propane, isosorbate, spiroglycol and the like. Especially, it is a preferable aspect that ethylene glycol is a main component from a viewpoint that superposition | polymerization is easy.

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

  In the laminated film of the present invention, it is also preferable that the diol component comprises at least two kinds and the content of the main diol component is 50 mol% or more and 90 mol% or less. In this case, since the orientation and crystallinity of the crystalline polyester can be controlled, it becomes easier to obtain a laminated film more suitable for the laminated vitrification process.

In the laminated film of the present invention, it is also preferable that the diol component constituting the crystalline polyester A comprises an alkylene glycol having 2 to 5 carbon atoms. When the diol component constituting the crystalline polyester A contains an alkylene glycol having 2 to 5 carbon atoms, it is possible to lower the glass transition temperature as a resin while maintaining the orientation and crystallinity. The laminated film can be shrunk, and it becomes easier to obtain a laminated film more suitable for the laminated vitrification process. In the laminated film of the present invention, the main dicarboxylic acid component and diol constituting the crystalline polyester A It is also preferred that the sum of the dicarboxylic acid and diol component other than the components is less than 20 mol% (in this case, the sum of all dicarboxylic acid components and the diol component is 200 mol%). Since the sum of the main dicarboxylic acid component and the dicarboxylic acid other than the diol component and the diol component is less than 20 mol%, it becomes easy to mold at a lower temperature while having appropriate crystallinity, and therefore a more laminated glass forming process. It is easy to obtain a laminated film suitable for the above, and the actually obtained laminated film can have high polarization reflection performance.

  More preferably, the layer A made of the crystalline polyester A of the present invention is made of a mixture of two or more kinds of crystalline polyesters. Even in the case of a mixture of two or more kinds of crystalline polyesters, the orientation and crystallinity of the crystalline polyester can be controlled, so that it becomes even easier to obtain a laminated film suitable for the laminated glassing process. In addition, when controlling the orientation and crystallinity with the composition of the crystalline polyester, there are cases where problems occur in drying and extrusion of the resin when forming a film because the crystallinity of the resin itself is reduced. When two kinds of crystalline polyesters are mixed, each resin is excellent in drying and extrudability, so that it becomes easy to stably form a film. As a further preferable effect of mixing two or more kinds of polyesters, the crystalline polyesters are dispersed with a small region called a domain without being completely mixed, so that crystallization proceeds in each domain, While excellent in controlling the orientation and crystallinity of the crystalline polyester, it exhibits the effect of suppressing film-forming troubles such as roll adhesion during stretching.

  In the laminated film of the present invention, it is also preferred that the A layer made of the crystalline polyester A contains a compound having an ester bond having a molecular weight of 500 or more and 10,000 or less. By including a compound having such a molecular weight, the glass transition temperature is suppressed by suppressing the entanglement of the polyester molecular chain while maintaining high polarization reflection characteristics without lowering the crystallinity, and thus more laminated glass. It becomes easy to obtain a laminated film suitable for the conversion step. On the other hand, when the molecular weight exceeds 10,000, the effect of suppressing the entanglement of the polyester molecular chains and the effect of increasing the crystallinity may be lowered. On the other hand, if the molecular weight is less than 500, the additive tends to bleed out. The molecular weight here refers to the number average molecular weight. More preferably, it is 3000 or less. The lower limit is preferably 1000 or more.

Moreover, in the laminated | multilayer film of this invention, it is also preferable that content of the compound which has an ester bond of molecular weight 500 or more and 10,000 or less is the range of 2 to 10 weight% with respect to the layer containing the said compound. If it is less than 2% by weight, the effect of suppressing the entanglement of the polyester molecular chains may not be sufficiently obtained. When the amount is more than 10% by weight, the effect of suppressing the entanglement of the polyester molecular chains becomes too large, the polyester molecular chains are not oriented, and the mechanical strength and transparency may be impaired. By being in the range of 2% by weight to 10% by weight, it is possible to achieve both high polarization reflection characteristics and appropriate vitrification process.
The compound having an ester bond is more preferably an aromatic ester containing a butylene group. By including a butylene group, the effect of suppressing the entanglement of the polyester molecular chain of the polyester film and the effect of increasing the crystallinity are increased, and by being an aromatic ester, the compatibility with the polyester is high and the internal haze is lowered. Can do. In particular, an aromatic ester composed of terephthalic acid, butylene group, and ethylhexyl group is preferable.

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

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

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

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

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

  Further, in order to obtain a laminated film having an interference reflection function when the laminated film is re-stretched to obtain a re-stretched film, the thermoplastic resin B has a melting point that is 20 ° C. lower than the melting point of the crystalline polyester A. A crystalline resin is also preferably used. In this case, by further performing a heat treatment at a temperature between the melting point of the thermoplastic resin B and the melting point of the crystalline polyester A, it can be completely relaxed in the heat treatment step. The refractive index difference can be maximized. Preferably, the difference in melting point between the crystalline polyester A and the thermoplastic resin B is 40 ° C. or higher. In this case, since the temperature selection range in the heat treatment step is widened, the relaxation of the orientation of the thermoplastic resin B can be promoted and the orientation of the crystalline polyester can be more easily controlled.

  As a preferable combination of the crystalline polyester A and the thermoplastic resin B, the absolute value of the difference between the SP values is preferably 1.0 or less. When the absolute value of the difference in SP value is 1.0 or less, delamination between the A layer and the B layer is difficult to occur. More preferably, the crystalline polyester A and the thermoplastic resin B are made of a combination provided with the same basic skeleton.

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

  Further, in order to obtain a laminated film having an interference reflection function when the laminated film is drawn again to obtain a redrawn film, the glass transition temperature of the thermoplastic resin B is 10 ° C. or more than the glass transition temperature of the crystalline polyester A. Preferably it is low. In this case, since the orientation in the thermoplastic resin B does not proceed when the optimum stretching temperature is taken to stretch the crystalline polyester in each stretching step, the difference in refractive index from the A layer made of the crystalline polyester. Can be greatly increased. More preferably, the glass transition temperature of the thermoplastic resin B is 20 ° C. or more lower than the glass transition temperature of the crystalline polyester A. In a production method suitable for obtaining the laminated film of the present invention to be described later, oriented crystallization of the thermoplastic resin B is likely to proceed, and a desired interference reflection function may not be obtained. However, the glass transition of the thermoplastic resin B may occur. By making the temperature 20 ° C. or more lower than the glass transition temperature of the crystalline polyester A, oriented crystallization can be suppressed.

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

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

  In the laminated film of the present invention, the reflectance at an incident angle of 10 ° for the polarization component parallel to the incident surface including the orientation axis direction of the laminated film is R1, and the incident surface including the orientation axis direction of the laminated film is On the other hand, when the reflectance at an incident angle of 10 ° is R2 for a polarized light component perpendicular to it, the reflectance at a wavelength of 550 nm preferably satisfies the following expressions (1) and (2). By satisfying the following formulas (1) and (2), it is possible to impart a polarization reflection characteristic of reflecting either polarized light and transmitting the other polarized light.

In order to obtain a film satisfying the following formula (1), the refractive index difference between the A layer and the B layer in the orientation axis direction of the laminated film is 0.02 or less, more preferably 0.01 or less, and still more preferably. , 0.005 or less can be adjusted by the combination of resins. Further, in order to obtain a film satisfying the following formula (2), the difference in refractive index between the A layer and the B layer in the direction perpendicular to the orientation axis direction of the laminated film is 0.08 or more, more preferably 0. It can be adjusted by selecting a resin combination of 1 or more, more preferably 0.15 or more, and film forming conditions. Examples of the optimum combination are as described above.
・ R2 (550) ≦ 40% (1)
・ R1 (550) ≧ 70% (2)
Next, the preferable manufacturing method of the laminated | multilayer film of this invention is demonstrated below.

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

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

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

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

  The casting film thus obtained is preferably biaxially stretched. Here, biaxial stretching refers to stretching the film in the longitudinal direction and the width direction.

  Furthermore, as a suitable biaxial stretching method for obtaining the laminated film of the present invention, the film is stretched in the film longitudinal direction at a magnification of 2 to 45 times, then stretched in the film width direction at 2 to 45 times, and further the film longitudinal direction again. Drawing in the direction is 1.3 to 4 times. The details are as follows.

  The obtained cast film is first stretched in the longitudinal direction. Stretching in the longitudinal direction is usually performed by the difference in the peripheral speed of the roll. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. Although it changes with kinds of resin as a draw ratio, it is preferred that it is 2-45 times. The purpose of the first stretching in the longitudinal direction is to provide the minimum orientation necessary for improving the uniform stretchability in the subsequent stretching in the film width direction. Therefore, when the stretching ratio is set to a ratio larger than 45 times, a film having a sufficient stretching ratio may not be obtained during stretching in the film width direction described later and re-stretching in the longitudinal direction performed after the process. Moreover, when the draw ratio is less than 2, the necessary minimum orientation cannot be imparted at the time of stretching, and thickness unevenness may occur in the film longitudinal direction, resulting in a reduction in quality. Further, the stretching temperature is preferably a temperature of glass transition temperature to glass transition temperature + 30 ° C. of crystalline polyester A constituting the laminated film.

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

  Subsequently, the uniaxially stretched film is stretched in the width direction. Stretching in the width direction is usually performed by using a tenter and transporting the film while holding both ends of the film with clips. Although it changes with kinds of resin as a magnification of extending, it is usually preferred that it is 2 to 4.5 times. The purpose of stretching in the width direction is to provide the minimum orientation necessary for imparting high stretchability in the subsequent stretching in the film longitudinal direction. For this reason, when the stretching ratio is set to a ratio larger than 4.5 times, a film having a sufficient stretching ratio may not be obtained at the time of re-stretching in the longitudinal direction of the film that is performed following this step. Further, when the draw ratio is less than 2, the thickness may be uneven in the film width direction at the time of drawing, and the quality may be lowered. Moreover, it is preferable that extending | stretching temperature is between the glass transition temperature of the crystalline polyester A which comprises a laminated | multilayer film-glass transition temperature +30 degreeC, or between the glass transition temperature-the crystallization temperature of crystalline polyester.

  Subsequently, the obtained biaxially stretched film is stretched again in the longitudinal direction. This stretching in the longitudinal direction is usually performed by the difference in the peripheral speed of the roll. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. Although the draw ratio varies depending on the type of resin, it is preferably 1.3 to 4 times. The purpose of this second stretching in the longitudinal direction is to orient the film as strongly as possible in the longitudinal direction of the film, and thus the resin is strongly oriented by stretching in the longitudinal direction again, resulting in the orientation of the laminated film. Either in the axial direction or the direction orthogonal to the orientation axis direction, the thermal shrinkage rate when heated at Tg (h) -20 ° C. for 6 hours is 0.5% or more, or in the orientation axis direction of the laminated film The Young's modulus can be 6 GPa or more. In particular, the higher the draw ratio in the longitudinal direction, the easier it is to set the thermal shrinkage rate to 1.0% or higher or the Young's modulus to 10 GPa or higher when heated at Tg (h) -20 ° C. for 6 hours. . Moreover, it is preferable that extending | stretching temperature is the glass transition temperature of the crystalline polyester A which comprises a laminated | multilayer film-glass transition temperature +80 degreeC.

  Thus, the obtained stretched film can also be heat-treated 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 heat treatment, the effect of increasing the Young's modulus by promoting oriented crystallization is obtained. After being heat-treated in this way, it is uniformly cooled and then cooled to room temperature and wound up. In addition, if necessary, a relaxation treatment or the like can be performed during the slow cooling after the heat treatment.

  The laminated film obtained by the manufacturing method as described above not only exhibits a high thermal shrinkage even at a temperature lower than the glass transition temperature or has a high Young's modulus, but also satisfies the above formulas (1) and (2). It can also be set as the laminated film provided with. This is because the orientation of the A layer made of crystalline polyester A can be made stronger in the film longitudinal direction during the second stretching in the film longitudinal direction. As a result, the refractive index in the film longitudinal direction and the film This is because a difference occurs in the refractive index in the film width direction perpendicular to the longitudinal direction. Further, as the thermoplastic resin B, by selecting an amorphous resin or a combination of the crystalline polyester A and the thermoplastic resin B having a difference in glass transition temperature and melting point that can relax the orientation in the stretching process and the heat treatment process. Further, the orientation of the thermoplastic resin B can be suppressed, and the polarization reflection property is imparted.

  The above film forming process is compared with Patent Document 3 (Japanese Patent Publication No. 2002-509282), which discloses a detailed manufacturing method of a film having polarization reflection characteristics disclosed in Patent Document 1 and Patent Document 1. . In Patent Document 3, a film having polarization reflection characteristics is obtained by uniaxial stretching in the film width direction or biaxial stretching in the film width direction and the longitudinal direction. On the other hand, in this invention, a laminated | multilayer film is obtained by extending | stretching a total of 3 times, twice in the film longitudinal direction and once in the width direction. Since the orientation of the resin is strengthened as the draw ratio increases, the laminated film oriented more strongly than the film producing method disclosed in Patent Document 3 can be obtained by using the laminated film producing method of the present invention. Can be obtained. Due to the strength of this orientation, in addition to improving the Young's modulus, it is possible to develop a high shrinkage behavior at a temperature below the glass transition temperature at which no shrinkage behavior is inherently generated.

Next, an example of the laminated glass forming process of the laminated film thus obtained will be described below.
Resin sheet used as an intermediate film represented by polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer, cut laminated film, resin A sheet and the other glass are placed, or pre-crimped by heating for about 1 hour in an atmosphere of 120 ° C. 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. Here, in the steps of temporary pressure bonding and main bonding, by using the laminated film of the present invention, the shrinkage of the laminated film also occurs in accordance with the start of shrinkage of the polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer. An excellent laminated film can be obtained.

  The laminated glass thus obtained can be suitably used for liquid crystal projection applications. In particular, it can be suitably used for a head-up display application including a light source and a liquid crystal module. At this time, the light source is not particularly limited, and is equipped with mercury, metal halide, halogen, fluorescent lamp, white LED lamp, RGB three-wavelength LED lamp, and the like, and is excellent in terms of low power consumption. Is preferred. In addition, the liquid crystal module at this time is not particularly limited. For example, an STN (Super Twisted Nematic) method, a TFT (Thin Film Transistor) method, a DSTN (Dual Super Twisted Nematic), and an FSTN (Film-Compensated Method) method are used. and so on.

  By including the liquid crystal module, the image projected on the laminated glass for liquid crystal projection has a specific polarization state. The effect in the case of having a polarization reflection characteristic like the laminated film of the present invention will be described with a model case where the reflectance of one polarization is 100% and the reflectance of the other polarization is 0%. At this time, the reflectance in a non-polarized state is 50%. If a laminated film in a direction that can reflect the image projected from the liquid crystal module is disposed, the image from the liquid crystal module is displayed with a reflectance of 100%, so that the amount of light reaching the driver is 100%. On the other hand, information outside the windshield in a non-polarized state is reflected at a reflectance of 50%, so the amount of light reaching the driver is 50%. On the other hand, when a film with a reflectance of 50% having no polarization reflection characteristic is used in the same manner, the light quantity of information from the liquid crystal module reaching the driver and the light quantity of information from the outside of the front are 50%. The laminated film of the present invention can obtain information from the liquid crystal module twice as bright. Furthermore, by adjusting the degree of polarization, it is possible to improve the visibility outside the windshield while increasing the amount of light from the liquid crystal module, which makes it a head-up display that is excellent in terms of safety and visibility. is there.

  In addition, although the same effect can be obtained even if it is attached to the windshield without using laminated glass, adhesion peeling, scratches, deterioration of the resin, etc. occur during long-term use, and as a result, transparency, appearance deterioration, and safety There is a concern that the sex will decline. On the other hand, these problems can be prevented by encapsulating the laminated film inside the laminated glass, and a head-up display suitable for long-term use can be obtained.

  The laminated film of the present invention can be used as a brightness enhancement film provided inside a liquid crystal projector used for a head-up display in addition to laminated glass. In this case, by previously reflecting and reusing the polarized light that was originally absorbed by the polarizing plate provided in the liquid crystal projector, it is possible to suppress the light from being absorbed by the polarizing plate, and the same amount of light. Even if the light source is irradiated from the light source, the amount of light actually emitted from the liquid crystal projector can be increased, and the effect of increasing the brightness, and consequently improving the safety associated with the clear display and reducing the power required for the liquid crystal projector can be obtained. It is

Hereinafter, the laminated film of the present invention will be described using examples.
[Methods for measuring physical properties and methods for evaluating effects]
The characteristic value evaluation method and the effect evaluation method are as follows.

(1) Number of layers:
The layer structure of the laminated film was determined by observing a sample cut out using a microtome using a transmission electron microscope (TEM). That is, using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), a cross-sectional photograph of the film was taken under the condition of an acceleration voltage of 75 kV, and the number of layers was confirmed.

(2) Measurement of Young's modulus and identification of the orientation axis direction of the laminated film:
The laminated film was cut into a strip shape having a length of 150 mm and a width of 10 mm to prepare a sample. Using a tensile tester (Orientec Tensilon UCT-100), an initial tensile chuck distance was set to 50 mm, and a tensile speed was set to 300 mm / min. The measurement was carried out in an atmosphere at room temperature of 23 ° C. and a relative humidity of 65%, and the Young's modulus was obtained from the obtained load-strain curve. The measurement was performed 5 times for each sample, and the average value of each was determined as Young's modulus. This measurement was performed by changing the direction every 10 ° in the film plane, and the direction in which the Young's modulus was maximized was taken as the orientation direction of the laminated film.

(3) Measurement of reflectance for incident light having a polarization component:
The sample was cut out at 5 cm × 5 cm from the center in the alignment axis direction on the line segment having the maximum length in the alignment axis direction. A basic configuration using an integrating sphere attached to a spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd., and measurement was performed with reference to an auxiliary white plate of aluminum oxide attached to the apparatus. The sample was placed behind the integrating sphere with the orientation direction of the laminated film being the vertical direction. In addition, a polarizer made by the attached Grantera Co., Ltd. was installed, and linearly polarized light whose polarization component was polarized at 0 and 90 ° was incident, and the reflectance at a wavelength of 250 to 1500 nm was measured.

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

(4) Heat of crystal melting ΔHm and glass transition temperature:
Sampling was performed from the laminated film to be measured, and the DSC curve of the measurement sample was measured according to JIS-K-7122 (1987) using differential calorimetry (DSC). In the test, the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min, and the melting enthalpy and the glass transition temperature at that time were measured. The apparatus etc. which were used are as follows.
・ Device: “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd.
・ Data analysis "Disk Session SSC / 5200"
Sample mass: 5 mg.

(5) Thermal contraction rate Samples were cut out at a size of 150 mm × 10 mm and marked at 100 mm intervals in the sample longitudinal direction. The interval between the marks was measured using a Nikon universal projector (Model V-16A), and the value was designated as A. Next, the sample was hung in a gear oven under a load of 3 g and left in an atmosphere of Tg (h) -20 ° C. or 85 ° C. for 6 hours. Next, the sample was taken out and cooled, and then the interval between the first marks was measured. At this time, the thermal contraction rate was calculated from the following formula (3). The number of n was set to 3, and the average value was obtained, and measurement was performed for each of the film orientation axis direction and the direction orthogonal to the orientation axis direction.
Thermal contraction rate (%) = 100 × (A−B) / A (3).

(6) Workability:
A roll-shaped film was introduced into a punching machine, and punching was performed using a square mold having a length of 100 mm. The following A, B and C evaluations were made. A and B were accepted.
A: The film could be continuously conveyed and processed without breaking.
B: Although the film can be continuously conveyed without breakage, the film has a slight breakage in part. C: The film is completely broken and continuous processing in the longitudinal direction cannot be performed.

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

Example 1
As crystalline polyester A, 2,6-polyethylene naphthalate (PEN) having a melting point of 266 ° C. and a glass transition temperature of 122 ° C. was used. Further, the thermoplastic resin B is an amorphous resin having no melting point, and 25 mol% of 2,6-naphthalenedicarboxylic acid having a glass transition temperature of 103 ° C., 25 mol% of terephthalic acid, and 50 mol% of ethylene glycol are copolymerized. Copolymerized PEN (copolymerized PEN1) was used.

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

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

  The obtained cast film was heated with a roll group set at a temperature of 120 ° C., stretched 3.3 times with a roll set at a temperature of 135 ° C. in the longitudinal direction of the film, and then cooled once. The uniaxially stretched film thus obtained was guided to a tenter, preheated with hot air at a temperature of 115 ° C, stretched 3.5 times in the film width direction at a temperature of 135 ° C, and further in the longitudinal direction of the film at a temperature of 160 ° C. To obtain a laminated film as a film roll.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. On the other hand, although it showed interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, it can be displayed when used as a head-up display with very high transparency, but the image is It was a little dark.

  The obtained laminated film was sandwiched between a sheet of sheet glass and polyvinyl butyral having a thickness of 0.7 mm on a 10 cm square having a thickness of 3 mm, vacuumed at 140 ° C. for 5 minutes at Nisshinbo LAMINATOR0303S, and then a pressure of 1.3 MPa for 10 minutes. To make a laminated glass.

  The obtained laminated glass was free of wrinkles and bubbles and had an excellent appearance.

(Example 2)
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 101 slits and the film was again stretched in the film longitudinal direction at a draw ratio of 1.7 times.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and is more suitable for a head-up display by showing a higher polarization reflection characteristic than that of Example 1. It was a thing.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

(Example 3)
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 201 slits and the film was stretched again in the film longitudinal direction at a draw ratio of 1.9 times.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and exhibits high polarization reflection characteristics as compared with Example 2, and is clearly displayed as a head-up display. It was possible.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

Example 4
A laminated film was obtained in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having 401 slits and the film was stretched again in the film longitudinal direction at a draw ratio of 2.2.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and exhibits high polarization reflection characteristics compared to Example 3, and is suitable as a head-up display. Met.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

(Example 5)
Copolymerization of crystalline polyester with a glass transition temperature of 119 ° C., 2,6-naphthalenedicarboxylic acid 100 mol% as a dicarboxylic acid component, and ethylene glycol 90 mol% and neopentyl glycol 10 mol% as a diol component A laminated film was obtained in the same manner as in Example 4 except that PEN (copolymerized PEN2) was used and the stretching ratio when the film was stretched again in the longitudinal direction of the film was 2.6 times.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and exhibits higher polarization reflection characteristics than those of Example 4 and is suitable as a head-up display. It was a thing.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

(Example 6)
Copolymerized PEN copolymerized with crystalline polyester having a glass transition temperature of 117 ° C., using 90 mol% of 2,6-naphthalenedicarboxylic acid and 10 mol% of terephthalic acid as a dicarboxylic acid component, and 100 mol% of ethylene glycol as a diol component. A laminated film was obtained in the same manner as in Example 4 except that (copolymerization PEN3) was used and the draw ratio when the film was drawn again in the film longitudinal direction was 2.8 times.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and exhibits higher polarization reflection characteristics than those of Example 4 and is suitable as a head-up display. It was a thing.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

(Example 7)
A laminated film was obtained in the same manner as in Example 5 except that the stretch ratio when the film was stretched again in the longitudinal direction of the film was 3.0 times.

  The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. In addition, it exhibits interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and exhibits higher polarization reflection characteristics than those of Example 5, and is suitable as a head-up display. It was a thing.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

(Example 8)
A laminated film was obtained in the same manner as in Example 5 except that the stretching ratio when the film was stretched again in the longitudinal direction of the film was 2.2 times.

  The physical properties of the obtained laminated film are shown in Table 1. Although a slight decrease was seen as compared with Example 5, it exhibited a high thermal shrinkage even below the glass transition temperature and a high Young's modulus. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display It was suitable as.

  Further, the laminated glass obtained in the same manner as in Example 1 was free of wrinkles and bubbles and had an excellent appearance.

Example 9
A laminated film was obtained in the same manner as in Example 5 except that the stretching ratio when the film was stretched again in the film longitudinal direction was 1.8 times.

  The physical properties of the obtained laminated film are shown in Table 1. Although a slight decrease was seen as compared with Example 5, it exhibited a high thermal shrinkage even below the glass transition temperature and a high Young's modulus. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

  On the other hand, a slight fracture was seen in some samples in the punching process into a glass shape, and the laminated glass obtained in the same manner as in Example 1 can be used, but a slight wrinkle is seen. It was.

(Example 10)
Example 1 except that 10% by weight of copolymerized PEN1 and 90% by weight of copolymerized PEN2 were mixed and used as the crystalline polyester, and the stretching ratio when the film was stretched again in the longitudinal direction of the film was 3.2 times. 5 was used to obtain a laminated film.

  The physical properties of the obtained laminated film are shown in Table 1. Although somewhat higher than the glass transition temperature as compared with Example 5, it showed a high thermal shrinkage and was suitable for laminated glass processing. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

(Example 11)
As the crystalline polyester, the glass transition temperature is 112 ° C., 95 mol% of 2,6-naphthalenedicarboxylic acid and 5 mol% of isophthalic acid are used as the dicarboxylic acid component, and 90 mol% of ethylene glycol and 10 mol% of neopentyl glycol are used as the diol component. Copolymerized copolymer PEN (copolymerized PEN4) is an amorphous resin having no melting point as thermoplastic resin B, has a glass transition temperature of 98 ° C., and 50 mol% of 2,6-naphthalenedicarboxylic acid as a dicarboxylic acid component. , Using 50 mol% of terephthalic acid, 90 mol% of ethylene glycol as a diol component, and copolymerized PEN (copolymerized PEN5) copolymerized using 10 mol% of neopentyl glycol, and stretching the film again in the film longitudinal direction. Stretch ratio is 3.0 times Except that the A laminated film was obtained by the same manner as in Example 5.

  The physical properties of the obtained laminated film are shown in Table 1. Although somewhat higher than the glass transition temperature as compared with Example 5, it showed a high thermal shrinkage and was suitable for laminated glass processing. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

(Example 12)
Thermoplastic resin B is an amorphous resin having no melting point, has a glass transition temperature of 92 ° C., uses 35 mol% of 2,6-naphthalenedicarboxylic acid and 65 mol% of terephthalic acid as a dicarboxylic acid component, and ethylene glycol as a diol component Implementation was carried out except that 90 mol% and copolymerized PEN copolymerized using 10 mol% of neopentyl glycol (copolymerized PEN 6) were used, and the stretching ratio when the film was stretched again in the longitudinal direction of the film was 3.2 times. A laminated film was obtained in the same manner as in Example 1.

  The physical properties of the obtained laminated film are shown in Table 1. Although somewhat higher than the glass transition temperature as compared with Example 5, it showed a high thermal shrinkage and was suitable for laminated glass processing. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

(Example 13)
As a crystalline polyester, a glass transition temperature is 110 ° C., 90 mol% of 2,6-naphthalenedicarboxylic acid and 10 mol% of isophthalic acid are used as a dicarboxylic acid component, and 90 mol% of ethylene glycol and 10 mol% of neopentyl glycol are used as diol components. A laminated film was obtained in the same manner as in Example 5 except that the copolymerized PEN (copolymerized PEN7) was used and the stretching ratio when the film was stretched again in the longitudinal direction of the film was 2.8 times.

  The physical properties of the obtained laminated film are shown in Table 1. Although the heat shrinkage rate was slightly higher than that of Example 5 at 85 ° C., it was suitable for laminated glass processing. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

(Example 14)
As the crystalline polyester, 95% by weight of copolymerized PEN2 and 5% by weight of an aromatic ester having terephthalic acid, butylene group, and ethylhexyl group having a number average molecular weight of 2000 are mixed, and the film is stretched in the longitudinal direction of the film again. A laminated film was obtained in the same manner as in Example 5 except that the draw ratio was 3.2 times.

  The physical properties of the obtained laminated film are shown in Table 1. Although the heat shrinkage rate was slightly higher than that of Example 5 at 85 ° C., it was suitable for laminated glass processing. Further, it shows interference reflection characteristics derived from the difference in refractive index between crystalline polyester A and thermoplastic resin B, and shows a high polarization reflection characteristic although it is slightly lowered as compared with Example 5, and a head-up display Can be clearly displayed.

(Comparative Example 1)
As a cast film, a single-layer film of PEN was used, and the film (of Example 1 was used) except that the stretch ratio when the film was stretched again in the film longitudinal direction was 1.3 times. Corresponding to a laminated film).

The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. On the other hand, since it does not have a laminated structure, it does not show any specific reflection performance and is unsuitable for use as a head-up display.
On the other hand, since it broke in the punching process into a glass shape, it could not be continuously processed.

(Comparative Example 2)
A laminated film was used in the same manner as in Example 1 except that the laminating apparatus used was an apparatus having three slits and the stretching ratio when the film was stretched again in the film longitudinal direction was 1.3 times. Obtained.

The physical properties of the obtained laminated film are shown in Table 1. The heat shrinkage was high even below the glass transition temperature, and the Young's modulus was very high. On the other hand, since the number of layers is small, the reflection performance is hardly shown and it is unsuitable for use as a head-up display.
On the other hand, since it broke in the punching process into a glass shape, it could not be continuously processed.

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

  The uniaxially stretched film thus obtained is guided to a tenter, preheated with hot air at a temperature of 135 ° C., stretched 4.5 times in the film width direction at a temperature of 150 ° C., and further heat treated at 220 ° C. An axially stretched film was obtained as a film roll.

  The physical properties of the obtained laminated film are shown in Table 1. Although the shrinkage characteristics were hardly exhibited below the glass transition temperature, the Young's modulus was lower than that of Example 5. On the other hand, although it has high reflection performance, it has no polarization characteristics and is unsuitable for use as a head-up display.

  In addition, the laminated glass obtained in the same manner as in Example 1 showed many wrinkles and was unsuitable for a head-up display even in appearance.

(Comparative Example 4)
The cast film obtained in the same manner as in Example 5 was led to a tenter, preheated with hot air at a temperature of 135 ° C., and then stretched 5.0 times in the film width direction at a temperature of 150 ° C. to form a uniaxially stretched film as a film roll Got as.

  The physical properties of the obtained laminated film are shown in Table 1. Although the shrinkage characteristics were hardly exhibited below the glass transition temperature, the Young's modulus was lower than that of Example 5. On the other hand, it shows interference reflection characteristics derived from the difference in refractive index between the crystalline polyester A and the thermoplastic resin B, and shows high polarization reflection characteristics at the same level as compared with Example 5, in terms of optical characteristics. Then, it was suitable as a head-up display.

  Further, since it was broken in the punching process into a glass shape, it could not be continuously processed, and many wrinkles were observed even in the laminated glass obtained in the same manner as in Example 1, which was unsuitable for a head-up display in appearance. .

1. 1. Film orientation axis direction 2. Polarized light perpendicular to the incident plane including the film orientation axis direction Polarization parallel to the plane of incidence including the direction of the film orientation axis

The present invention relates to a laminated film and a laminated glass for liquid crystal projection using the same. More specifically, the present invention relates to a laminated film suitable for a head-up display having a good appearance when used as a laminated glass and having high transparency and display brightness when used as a head-up display.

Claims (9)

A laminated film in which a total of 11 layers or more of A layers made of crystalline polyester and B layers made of thermoplastic resin B different from the crystalline polyester are alternately laminated, and the Young in the orientation axis direction of the laminated film Of the glass transition temperature Tg (A) of the crystalline polyester and the glass transition temperature Tg (B) of the thermoplastic resin B, the glass transition temperature at a higher temperature is defined as Tg (h). The thermal shrinkage rate when heated at Tg (h) -20 ° C. for 6 hours in either the orientation axis direction or the direction perpendicular to the orientation axis direction of the laminated film is 0.5% or more. Laminated film. The heat shrinkage rate when the laminated film is heated at Tg (h) -20 ° C. for 6 hours in the orientation axis direction and the heat when heated at Tg (h) -20 ° C. for 6 hours in the direction perpendicular to the orientation axis direction. The laminated film according to claim 1, wherein the difference in thermal shrinkage from the shrinkage is 0.5% or more. 3. The laminated film according to claim 1, wherein the crystalline polyester comprises 50 mol% or more of naphthalenedicarboxylic acid among carboxylic acid components constituting the crystalline polyester. The laminated film according to any one of claims 1 to 3, wherein the crystalline polyester comprises an alkylene glycol having 2 to 5 carbon atoms as a diol component constituting the crystalline polyester. The laminated film according to any one of claims 1 to 4, wherein the layer A made of the crystalline polyester further contains a compound having an ester bond having a molecular weight of 500 or more and 10,000 or less. The thermal shrinkage rate when heated at 85 ° C. for 6 hours in either the orientation axis direction or the direction orthogonal to the orientation axis direction of the laminated film is 0.5% or more, The laminated film according to any one of the above. The reflectance at an incident angle of 10 ° for the polarization component parallel to the incident plane including the orientation axis direction of the laminated film is R1, and the polarization component perpendicular to the incident plane including the orientation axis direction of the laminated film is incident. The laminated film according to any one of claims 1 to 6, wherein the reflectance at a wavelength of 550 nm satisfies the following formulas 1 and 2 when the reflectance at an angle of 10 ° is R2.
・ R2 (550) ≦ 40% (1)
・ R1 (550) ≧ 70% (2) The laminated film according to any one of claims 1 to 7, wherein only one melting peak of 5 J / g or more is confirmed by differential scanning calorimetry (DSC). A laminated glass for liquid crystal projection, wherein a glass, a sheet made of polyvinyl alcohol, polyvinyl butyral, or an ethylene-vinyl alcohol copolymer, and the laminated film according to any one of claims 1 to 8 are overlapped.

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