Vehicle door glass

Abstract

To provide a vehicular door glass which is composed of a laminated glass formed by using an infrared-reflective film, which is excellent in heat insulating property, has good appearance, and is suppressed in the occurrence of poor appearance, especially, on an end.SOLUTION: A vehicular door glass includes a laminated glass in which a first glass plate, a first adhesive layer, an infrared-reflective film, a second adhesion layer and a second glass plate are laminated in this order, wherein the infrared-reflective film includes a laminate in which 100 or more layers of resin layers having different refractive indices are laminated, a thermal shrinkage in a direction with a maximum thermal shrinkage and a thermal shrinkage in a direction perpendicular to the maximum direction exceeds more than 0.6% and is less than 1.2% (thermal shrinkage is a reduction rate with a length in a prescribed direction before and after having been held at 150°C for 30 minutes), and in a region where the laminated glass is visible in a front view when the door glass for the vehicle is mounted on the vehicle, the outer periphery of the infrared-reflective film is positioned within a range to 10 mm inside from the outer periphery of the laminated glass in the front view.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle door glass, and particularly to a vehicle door glass made of laminated glass using an infrared reflection film.

Background Art

[0002] Conventionally, in order to reduce the air conditioning load of a vehicle and improve the comfort of passengers, a vehicle door glass using laminated glass with heat insulation properties is known. Among them, a laminated glass in which an infrared reflection film is disposed via an adhesive layer between two glass plates has been proposed.

[0003] The laminated glass is manufactured, for example, by stacking a glass plate, an adhesive layer, an infrared reflection film, an adhesive layer, and a glass plate in this order, and then integrally heating and pressing the whole. In the production of such laminated glass, due to uneven thickness of the adhesive layer resulting in uneven pressing, or the difference in thermal shrinkage rate between the film and the adhesive layer, the film develops uneven distortion and wrinkles, which impairs the appearance. Countermeasures to solve this problem are being studied.

[0004] For example, Patent Document 1 describes a technique of a multilayer laminated film having a function of interfering and reflecting infrared rays by alternately laminating resin layers having different refractive indexes and controlling the thickness of each layer to be laminated, and defining the thermal shrinkage stress of the film so as to suppress unevenness on the appearance.

[0005] Further, Patent Document 2 describes a laminated glass in which the thermal shrinkage rate, elastic modulus, or elongation of an infrared reflection film is controlled to be within a predetermined range in order to suppress wrinkles of the film that are likely to occur particularly at the peripheral portion of the main surface when a curved glass plate is used by bending.

[0006] Here, the technologies of Patent Document 1 and Patent Document 2 aim to suppress the deterioration of the appearance within the main surface of the laminated glass, and a certain degree of effect is recognized. However, in the case of a vehicle door glass, it is known that as the door glass moves up and down, the peripheral edge and end face of the main surface (hereinafter collectively referred to as the end portion) are particularly conspicuous, and the appearance of the end portion becomes a problem.

[0007] For example, in order to protect the end portion of the infrared reflection film, the outer periphery of the film may be arranged inside the outer periphery of the glass plate in a plan view. In that case, particularly as the door glass moves up and down, there is a problem that the color tone of the door glass end portion changes and it looks shiny. On the other hand, when the outer periphery of the film is arranged close to the outer periphery of the glass plate in a plan view for improving the appearance, the infrared reflection film thermally contracts due to heating during manufacturing, and accordingly, the adhesive layer is drawn toward the center of the main surface, resulting in a problem of poor appearance at the glass end portion.

[0008] However, as described above, in Patent Document 1 and Patent Document 2, although the deterioration of the appearance within the main surface of the laminated glass caused by the infrared reflection film is suppressed, the problem of the end portion being shiny and the problem of the appearance caused by the drawing of the adhesive layer that occur when used for a vehicle door glass are not solved.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a vehicle door glass made of laminated glass using an infrared reflection film, which has excellent heat insulation properties, good appearance, and particularly suppresses the occurrence of poor appearance at the end portion.

Means for Solving the Problem

[0011] The vehicle door glass of the present invention is a vehicle door glass including laminated glass in which a first glass plate, a first adhesive layer, an infrared reflection film, a second adhesive layer, and a second glass plate are laminated in this order, wherein the infrared reflection film includes a laminate in which 100 or more resin layers having different refractive indexes are laminated, the infrared reflection film has a heat shrinkage rate in the direction where the heat shrinkage rate is maximum exceeding 0.6% and less than 1.2%, and a heat shrinkage rate in the direction perpendicular to the direction exceeding 0.6% and less than 1.2%, and the heat shrinkage rate of the infrared reflection film in a predetermined direction is the shrinkage rate of the length in the predetermined direction before and after holding the infrared reflection film at 150 ° C for 30 minutes, when the laminated glass is attached to a vehicle, in a region where the laminated glass is visible in a front view, the outer periphery of the infrared reflection film is located within a range of 10 mm inward from the outer periphery of the laminated glass in the front view.

Advantages of the Invention

[0012] According to the present invention, there is provided a vehicle door glass made of laminated glass using an infrared reflection film, which has excellent heat insulation properties, good appearance, and particularly suppresses the occurrence of appearance defects at the ends.

[0013] In addition, in laminated glass using an infrared reflection film, a phenomenon in which the contour of the reflected image appears to fluctuate, so-called orange peel problem, is also known, but according to the present invention, the occurrence of orange peel can also be suppressed.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to these embodiments, and these embodiments can be changed or modified without departing from the spirit and scope of the present invention.

[0016] The vehicle door glass of the embodiment (hereinafter simply referred to as "door glass") includes a laminated glass having a first glass plate, a first adhesive layer, an infrared reflection film, a second adhesive layer, and a second glass plate, which are laminated in this order, and the configuration of the infrared reflection film satisfies the following requirements (1) to (3). (1) The infrared reflection film includes a laminate in which 100 or more resin layers having different refractive indexes are laminated. (2) The infrared reflection film has a heat shrinkage rate in the direction where the heat shrinkage rate is maximum exceeding 0.6% and less than 1.2%, and a heat shrinkage rate in the direction perpendicular to the direction exceeding 0.6% and less than 1.2%. However, the heat shrinkage rate of the infrared reflection film in a predetermined direction is the shrinkage rate of the length in the predetermined direction before and after holding the infrared reflection film at 150°C for 30 minutes. (3) When the laminated glass is attached to the vehicle, in the region where the laminated glass is visible in a front view, the outer periphery of the infrared reflection film is located within a range of 10 mm inward from the outer periphery of the laminated glass in a front view.

[0017] The infrared reflection film has infrared reflectivity by interference reflection by satisfying the requirement of (1). By satisfying the requirement of (2) for the infrared reflection film, the drawing-in of the adhesive layer is suppressed during the production of the laminated glass, and by satisfying the requirement of (3), the glare when made into a laminated glass is suppressed, and the appearance defect at the end is suppressed. As a result, a door glass of the embodiment having excellent heat insulation properties, good appearance, and particularly suppressed occurrence of appearance defects at the end can be obtained. Hereinafter, the door glass of the embodiment will be described with reference to the drawings.

[0018] FIG. 1 is a plan view of an example of a laminated glass constituting a door glass according to an embodiment. FIG. 2 is a cross-sectional view taken along the line X-X of the laminated glass shown in FIG. 1. FIG. 3 shows a side view of an automobile having a door glass which is an example of the embodiment shown in FIG. 1.

[0019] In this specification, "upper", "lower", "front", and "rear" indicate the upper side, lower side, front side, and rear side of the door glass, respectively, when the door glass is mounted on a vehicle. The "vertical direction" of the door glass indicates the vertical direction of the door glass when the door glass is mounted on a vehicle, and a direction orthogonal to the vertical direction is referred to as the "vehicle width direction".

[0020] In this specification, the first glass plate, the first adhesive layer, the infrared reflection film, the second adhesive layer, the second glass plate, and the door glass each have two main surfaces facing each other, and have end surfaces connecting the two main surfaces. In this specification, the peripheral portion of the main surface indicates a region having a certain width from the outer periphery of the main surface toward the central portion. The peripheral portions and end surfaces of both main surfaces are collectively referred to as the end portion. Also, in this specification, the outer peripheral side portion viewed from the center of the main surface is referred to as the outer side, and the central side portion viewed from the outer periphery of the main surface is referred to as the inner side. In this specification, "substantially the same shape" and "the same size" indicate states that are regarded as having the same shape and the same size when viewed by a person. In other cases as well, "substantially" has the same meaning as above. Also, "~" representing a numerical range includes the upper limit value and the lower limit value.

[0021] The laminated glass 10 (hereinafter also referred to as "door glass 10") used as the door glass shown in FIGS. 1 and 2 is formed by laminating a first glass plate 1, a first adhesive layer 3, an infrared reflection film 5, a second adhesive layer 4, and a second glass plate 2 in that order. The first glass plate 1, the first adhesive layer 3, the second adhesive layer 4, and the second glass plate 2 have main surfaces that are substantially the same shape and the same size as each other.

[0022] In the laminated glass 10, the shape of the main surface of the infrared reflection film 5 is substantially similar to the shape of the main surface of the first glass plate 1. When the laminated glass 10 is attached to a vehicle, in the region where the laminated glass 10 is visible in a front view (hereinafter also referred to as the "visible region"), the outer periphery (indicated by a dashed-dotted line in FIG. 1) is located within a range of 10 mm inward from the outer periphery of the laminated glass 10 in a front view.

[0023] The automobile 100 shown in FIG. 3 has the laminated glass 10 shown in FIG. 1. In the automobile 100, the front side door S and the rear side door S each include a door panel 20 and a door glass 10 that is vertically movably disposed on the door panel 20. In FIG. 3, for the front side door S, when the door glass 10 is raised to the highest position, that is, when the window is closed, the door glass 10 is indicated by a dashed line. Also, when the door glass 10 is lowered by a distance L from the position where the door glass 10 is raised to the highest position, the door glass 10 is indicated by a solid line and a dashed line.

[0024] In the automobile 100, the line connecting the upper ends of the front and rear door panels 20, that is, the lower end of the vehicle opening, is called the belt line VL. FIG. 1 shows the position of the belt line VL on the door glass 10 when the door glass 10 is attached to the automobile 100 and raised to the highest position (when the door glass is completely closed). In this specification, in the door glass 10, the visible region is the region located above the belt line VL in the state where the door glass 10 is attached to the automobile 100 and the door glass 10 is raised to the highest position as shown in FIG. 1. The region located below the belt line VL in this state is the non-visible region.

[0025] FIG. 3 shows that when the window is closed, none of the end faces of the door glass 10 can be seen, but when the window is opened, a part of it becomes visible. In the door glass 10, at least in the region located above the belt line VL in the state where the door glass 10 is attached to the automobile 100 and the door glass 10 is raised to the highest position, if the requirement of (3) above is satisfied, rattling can be suppressed. Hereinafter, each component of the door glass 10 will be described. [Infrared Reflection Film] The infrared reflection film 5 on the door glass 10 satisfies the requirements (1) to (3) above. The infrared reflection film 5 preferably further satisfies either or both of the following requirements (4) and (5). (4) The infrared reflection film has a thickness of 120 μm or less. (5) When the laminated glass is attached to the vehicle, the minimum radius of curvature of the outer periphery in the front view is 8 mm or more in the visible region of the laminated glass.

[0026] According to requirement (1), the infrared reflection film includes a laminate in which 100 or more resin layers having different refractive indices are laminated. The infrared reflection film 5 has infrared reflectivity by including the laminate. The infrared reflection film 5 may be composed only of the laminate, and may optionally have another layer, for example, a protective layer described later, as long as the effects of the present invention are not impaired. Another layer in the infrared reflection film is preferably composed of resin from the viewpoint of durability.

[0027] Regarding requirement (1), in the infrared reflection film 5, the types of resin layers having different refractive indices constituting the laminate may be two or more, preferably two or more and four or less, and particularly preferably two from the viewpoint of ease of manufacture. When two resin layers having different refractive indices are used, the resin layer having a relatively higher refractive index is defined as the high refractive index layer, and the resin layer having a lower refractive index is defined as the low refractive index layer. In this case, the laminate is usually configured by alternately laminating the high refractive index layer and the low refractive index layer.

[0028] The refractive index in the resin layer is given as the refractive index at a wavelength of 589 nm measured using a sodium D line as a light source. The refractive index of the high refractive index layer is preferably in the range of 1.62 to 1.70, and the refractive index of the low refractive index layer is preferably in the range of 1.50 to 1.58. Also, the difference in refractive index between the high refractive index layer and the low refractive index layer is preferably in the range of 0.05 to 0.20, and more preferably in the range of 0.10 to 0.15.

[0029] The refractive index of the resin layer can be adjusted by appropriately adjusting the type of resin, the type of functional groups and skeletons in the resin, and the content of the resin. As the resin constituting the resin layer, a thermoplastic resin is preferred. Examples include polyolefins, alicyclic polyolefins, polyamides, aramids, acrylic resins, polyvinyl chlorides, polyvinylidene chlorides, polystyrenes, styrene copolymers, polycarbonates, polyesters, polyethersulfones, polyetheretherketones, modified polyphenylene ethers, polyphenylene sulfides, polyetherimides, polyimides, polyarylates, fluorine-containing resins, and the like.

[0030] Two or more resins with different refractive indices are appropriately selected from these resins, and a resin layer composed of the selected resins is laminated according to the above design to form a laminate. When selecting resins with different refractive indices, from the viewpoints of interlayer adhesion and the feasibility of realizing a high-precision laminated structure, preferably, a combination of resins containing the same repeating unit is selected. Among the above resins, polyester is preferred from the viewpoints of strength, heat resistance, and transparency, and it is preferable to select a combination containing the same repeating unit from polyesters. As the polyester to be selected, a polyester obtained by using an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol, or their derivatives is preferred.

[0031] Examples of the polyester to be selected include polyethylene terephthalate, polyethylene terephthalate copolymer, polyethylene naphthalate, polyethylene naphthalate copolymer, polybutylene terephthalate, polybutylene terephthalate copolymer, polybutylene naphthalate, polybutylene naphthalate copolymer, polyhexamethylene terephthalate, polyhexamethylene terephthalate copolymer, polyhexamethylene naphthalate, polyhexamethylene naphthalate copolymer, and the like. It is preferable to use one or more polyesters selected from the above polyesters.

[0032] Among these, the resins constituting the resin layers with different refractive indices preferably include a combination containing at least one selected from polyethylene terephthalate (hereinafter also referred to as "PET") and polyethylene terephthalate copolymer (hereinafter also referred to as "PET copolymer"). When the laminate is composed of alternately laminated two types of resin layers, for example, it is preferable that one is a resin layer made of PET and the other resin layer is made of a resin composed of a PET copolymer or a mixture of at least two selected from PET and PET copolymer (hereinafter also referred to as "mixed PET").

[0033] The PET copolymer is composed of an ethylene terephthalate unit, which is the same repeating unit as PET, and a repeating unit having another ester bond (hereinafter also referred to as "other repeating unit"). As the proportion of the other repeating unit (hereinafter also referred to as "copolymerization amount"), it is preferably 5 mol% or more due to the necessity of obtaining different refractive indices. On the other hand, since the difference in adhesion between layers and the difference in heat flow characteristics are small, it is preferably 90 mol% or less because it is excellent in the accuracy and uniformity of the thickness of each layer. More preferably, it is 10 mol% or more and 80 mol% or less.

[0034] In addition, when the mixed PET is a mixture of PET and PET copolymer or a mixture composed of two or more PET copolymers, it is preferable to mix each component so that the content ratio of the other repeating unit as a mixture is the same as the copolymerization amount in the above PET copolymer.

[0035] Between the resin layers with different refractive indices, the absolute value of the difference in glass transition temperature is preferably 20°C or less. When the absolute value of the difference in glass transition temperature is greater than 20°C, the thickness uniformity may be poor when forming an infrared reflection film including the laminate, and there may be variations in infrared reflectivity. Also, when molding an infrared reflection film including the laminate, problems such as over-drawing are likely to occur.

[0036] The blended PET preferably contains, as other repeating units, repeating units derived from spiroglycol as a raw material diol. Hereinafter, for the repeating units derived from raw material components, they are denoted by attaching the unit to the raw material compound name. For example, the repeating unit derived from spiroglycol is denoted as "spiroglycol unit". That the blended PET contains the spiroglycol unit means that the blended PET contains a PET copolymer having the spiroglycol unit. The blended PET may consist only of a PET copolymer having the spiroglycol unit, or may be a mixture of the PET copolymer and PET. In the following description, that the blended PET contains the unit of a specific compound has the same meaning as when the blended PET contains the spiroglycol unit. The blended PET containing the spiroglycol unit is preferable because the difference in glass transition temperature from PET is small.

[0037] The blended PET preferably contains, as other repeating units, in addition to the spiroglycol unit, cyclohexanedicarboxylic acid units. The blended PET containing the spiroglycol unit and the cyclohexanedicarboxylic acid unit has a small difference in glass transition temperature from PET and a large difference in refractive index from PET, so that high infrared reflectivity is easily obtained when formed into a laminate.

[0038] When the blended PET contains the spiroglycol unit and the cyclohexanedicarboxylic acid unit, the copolymerization amount of the spiroglycol unit is preferably 5 mol% to 30 mol%, and the copolymerization amount of the cyclohexanedicarboxylic acid unit is preferably 5 mol% to 30 mol%.

[0039] The blended PET preferably also has a form in which it contains cyclohexanedimethanol units as other repeating units. The blended PET containing the cyclohexanedimethanol unit is preferable because the difference in glass transition temperature from PET is small.

[0040] When the mixed PET contains cyclohexanedimethanol units, the copolymerization amount of the cyclohexanedimethanol units is preferably 15 mol% or more and 60 mol% or less from the viewpoint of achieving both infrared reflectivity and interlayer adhesion. Note that cyclohexanedimethanol has cis or trans geometric isomers and also has chair or boat conformational isomers. Therefore, the mixed PET containing cyclohexanedimethanol units is less likely to be orientation-crystallized even when co-stretched with PET, has high infrared reflectivity, has even less change in optical properties due to heat history, and is less likely to cause problems during film formation.

[0041] From the viewpoint of film formation stability, the intrinsic viscosity (IV) of the PET and mixed PET used above is preferably 0.4 to 0.8, more preferably 0.6 to 0.75.

[0042] As described above, the combination of PET and mixed PET has been explained. In the present invention, the combination is not limited to the above, and different mixed PETs may be combined according to the required properties. In that case, a combination in which the types of units constituting the mixed PET are the same and the composition of the repeating units is different is preferred.

[0043] By laminating 100 or more resin layers having different refractive indexes in this way, the laminate has a function of interfering and reflecting infrared rays. The number of laminate layers of the laminate is not particularly limited as long as it is 100 or more. Preferably, the film thickness of the infrared reflection film 5 is appropriately adjusted within the range that satisfies the requirement of (4). In order to enhance the infrared reflectivity, the number of resin layers is preferably 400 or more, more preferably 600 or more. The upper limit of the number of laminate layers of the laminate is preferably about 5000 from the viewpoint of satisfying the preferable upper limit of the film thickness of the infrared reflection film 5.

[0044] The number of laminate layers of the resin layers and the layer thickness of each resin layer of the laminate are designed based on the refractive indexes of the resin layers used according to the required infrared reflectivity. For example, when using layer A and layer B as two types of resin layers having different refractive indexes, the layer thickness distribution preferably satisfies the following formula (i) for the optical thickness of the adjacent layer A and layer B.

[0045] λ = 2(n A d A + n B d B )(i) Here, λ is the reflection wavelength, n A is the refractive index of layer A, d A is the thickness of layer A, n B is the refractive index of layer B, d B is the thickness of layer B.

[0046] It is also preferable that the layer thickness distribution simultaneously satisfies formula (i) and the following formula (ii).

[0047] n A d A = n B d B (ii) By having a layer thickness distribution that simultaneously satisfies formula (i) and formula (ii), even-order reflections can be eliminated. As a result, for example, while increasing the average reflectance in the wavelength range of 850 nm to 1200 nm, the average reflectance in the wavelength range of 400 nm to 700 nm can be decreased, and an infrared reflection film 5 that is transparent and has high heat energy blocking performance can be obtained.

[0048] In addition to formula (i) and formula (ii), it is also preferable to use the 711711 structure (U.S. Patent No. 5360659) for the layer thickness distribution. The 711711 structure refers to a laminated structure in which six layers with layers A and B laminated in the order of ABABAB are used as one repeating unit, and the ratio of the optical thickness within the unit is 711711. By setting the layer thickness distribution to the 711711 structure, higher-order reflections can be eliminated. As a result, for example, while increasing the average reflectance in the wavelength range of 850 nm to 1400 nm, the average reflectance in the wavelength range of 400 nm to 700 nm can be decreased. Also, it is preferable that the reflection in the wavelength range of 850 nm to 1200 nm is based on a layer thickness distribution that simultaneously satisfies formula (i) and formula (ii), and the reflection in the wavelength range of 1200 nm to 1400 nm is based on the layer thickness distribution of the 711711 structure. By adopting such a layer thickness configuration, light can be efficiently reflected with a small number of laminated layers.

[0049] The layer thickness distribution is preferably one that increases or decreases from one side of the film surface to the opposite side, one that increases from one side of the film surface towards the film center and then decreases, or one that decreases from one side of the film surface towards the film center and then increases. As for the manner of change in the layer thickness distribution, those that change continuously, such as linearly, geometrically, or in an arithmetic progression, or those in which about 10 to 50 layers have substantially the same layer thickness and the layer thickness changes stepwise, are preferable.

[0050] In addition, the infrared reflection film 5 may have resin layers with a layer thickness of 3 μm or more as protective layers on both surface layers of the laminate. The layer thickness of the protective layer is preferably 5 μm or more, more preferably 10 μm or more. By increasing the layer thickness of the protective layer, effects such as suppression of flow marks and suppression of ripples in the transmittance - reflectance spectrum can be obtained.

[0051] Regarding requirement (4), the infrared reflection film 5 preferably has a thickness of 120 μm or less. When the thickness of the infrared reflection film 5 is 120 μm or less, the degassing property during the production of laminated glass is good. Also, the infrared reflection film 5 preferably has a thickness of 80 μm or more. Due to the rigidity possessed by the infrared reflection film 5 when its thickness is 80 μm or more, it is less affected by the thermal shrinkage of the first adhesive layer and the second adhesive layer during the production of laminated glass. Thereby, for example, it is easier to suppress the occurrence of orange peel. The thickness of the infrared reflection film 5 is preferably 85 μm or more and 115 μm or less, more preferably 90 μm or more and 110 μm or less.

[0052] Regarding requirement (2), the infrared reflection film 5 has a thermal shrinkage rate in the direction where the thermal shrinkage rate is maximum (hereinafter also referred to as the "maximum shrinkage direction") exceeding 0.6% and less than 1.2%, and a thermal shrinkage rate in the direction orthogonal to this direction (hereinafter simply referred to as the "orthogonal direction") exceeding 0.6% and less than 1.2%.

[0053] However, the thermal shrinkage rate of the infrared reflection film is the shrinkage rate of the length in a predetermined direction before and after holding the infrared reflection film at 150°C for 30 minutes. Specifically, the thermal shrinkage rate of the infrared reflection film can be measured as follows.

[0054] First, a strip-shaped test piece is cut out from the infrared reflection film 5 along the maximum shrinkage direction or the orthogonal direction. Since the infrared reflection film is manufactured by stretching the constituent material into a film shape as described later, stress exists in the infrared reflection film as residual stress. In particular, the residual stress is large and the film is prone to thermal shrinkage in the longitudinal direction, which is the flow direction during film manufacturing, i.e., the so-called MD direction. Therefore, usually, the MD direction is the maximum shrinkage direction, and the TD direction, which is the width direction, is the orthogonal direction.

[0055] The test piece is, for example, 150 mm in length and 20 mm in width. A pair of reference lines are marked on this test piece at intervals of approximately 100 mm in the longitudinal direction, and the length L1 between these reference lines is measured. The test piece is vertically suspended in a hot air circulation oven, heated to 150°C, held for 30 minutes, naturally cooled to room temperature, and held for 60 minutes. Then, the length L2 between the reference lines is measured. The thermal shrinkage rate can be calculated using the obtained L1 and L2 by the following formula (iii).

[0056] Thermal shrinkage rate = ((L1 - L2) / L1) × 100 [%] (iii) The infrared reflection film 5 can suppress the occurrence of orange peel when the thermal shrinkage rates in the maximum shrinkage direction and the orthogonal direction exceed 0.6%, and can suppress the occurrence of appearance defects caused by the pulling-in of the adhesive layer when it is less than 1.2%. The thermal shrinkage rate in the maximum shrinkage direction is preferably 0.65% or more and 1.10% or less, more preferably 0.70% or more and 0.90% or less. The thermal shrinkage rate in the orthogonal direction is preferably 0.65% or more and 1.10% or less, more preferably 0.70% or more and 1.10% or less. Also, the smaller the difference between the thermal shrinkage rate in the maximum shrinkage direction and the thermal shrinkage rate in the orthogonal direction, the more preferable it is, and it is particularly preferable that they are the same as each other.

[0057] The infrared reflection film 5 that satisfies requirements (1) and (2) and preferably satisfies requirement (4) can be manufactured, for example, by the following method. Note that the following example is a method for manufacturing the infrared reflection film 5 composed of a laminate using an A layer made of resin A and a B layer made of resin B as two resin layers with different refractive indexes. By appropriately changing this method, it is also possible to manufacture an infrared reflection film using three or more resin layers or an infrared reflection film having another layer such as a protective layer.

[0058] The infrared reflection film composed of a laminate using the A layer and the B layer can be manufactured by a method including the following steps (a) to (c). If an infrared reflection film that satisfies all of the requirements (1) and (2) is obtained in steps (a) and (b), step (c) is not performed. That is, step (c) can be an optional step. (a) A step of producing an unstretched laminate in which the A layer and the B layer are alternately laminated so that the number of laminations is the same but the layer thickness is different from that of the finally obtained laminate. (b) A step of stretching the unstretched laminate obtained in step (a) to adjust the layer thickness to obtain a laminate precursor. (c) A step of heat-treating the laminate precursor after step (b) to obtain a laminate in which the thermal shrinkage rate is adjusted to satisfy requirement (2). (a) Step of producing an unstretched laminate Resin A and resin B are prepared in the form of pellets or the like. The pellets are pre-dried in hot air or under vacuum as necessary and supplied to an extruder. In the extruder, the resin heated and melted above the melting point has its extrusion amount of the resin made uniform by a gear pump or the like, and foreign matters, denatured resin, etc. are removed through a filter or the like.

[0059] Resins A and B fed from different channels using two or more extruders are then conveyed to a multi-layer laminating device, where they are laminated into a molten laminate with the desired number of layers by the device, and then formed into the target shape by a die and discharged. The multi-layer laminated sheet discharged from the die is extruded onto a cooling body such as a casting drum and cooled and solidified to form an unstretched laminate. As the multi-layer laminating device, a multi-manifold die, a field block, a static mixer, etc. can be used. (b) Stretching step The unstretched laminate obtained in step (a) is stretched to produce a laminate precursor. The stretching method is usually biaxial stretching. The biaxial stretching method may be either sequential biaxial stretching or simultaneous biaxial stretching. Further, re-stretching may be performed in the MD direction and / or the TD direction. Simultaneous biaxial stretching is preferred from the viewpoints of suppressing the in-plane orientation difference and suppressing surface scratches. The biaxial stretching is preferably carried out in the range of not less than the glass transition temperature of the resin having the higher glass transition temperature among resins A and B and not more than the temperature + 120 °C.

[0060] The stretching ratios in the MD direction and the TD direction are adjusted so that the layer thickness of each layer in the obtained laminate becomes the designed layer thickness. Further, preferably, the stretching ratio and the stretching speed are adjusted so that the residual stress is about the same in the MD direction and the TD direction. Thereby, in the obtained infrared reflection film, a laminate precursor that satisfies the requirement (1) and preferably satisfies the requirement (4) can be obtained.

[0061] The laminate precursor obtained in the stretching step usually has a high residual stress and does not satisfy the requirement (2) in the infrared reflection film. Then, by obtaining the following (c) heat treatment, a laminate that satisfies the requirement (2) can be obtained. However, when the laminate precursor satisfies the requirement (2) as described above, it may be used as the laminate as it is. (c) Heat treatment step The heat treatment of the laminate precursor is generally carried out in a stretching machine. The heat treatment temperature is preferably lower than the melting point of the resin with the higher melting point among Resin A and Resin B and higher than the melting point of the resin with the lower melting point. Thereby, while the resin with the higher melting point maintains a high degree of orientation, the orientation of the resin with the lower melting point is relaxed, so that the refractive index difference between these resins can be easily provided. Furthermore, it becomes easy to reduce the thermal shrinkage stress accompanying the relaxation of orientation. As a result, the thermal shrinkage rate of the laminate can be easily adjusted within the range of (2).

[0062] In addition, the heat treatment may be performed so that the relaxation rate during the heat treatment is 0% or more and 10% or less, preferably 0% or more and 5% or less. Relaxation may be performed in either one or both of the TD direction and the MD direction. Also, it is preferable to perform micro-stretching of 2% or more and 10% or less during the heat treatment. Micro-stretching may be performed in either one or both of the TD direction and the MD direction. In this way, by adjusting the heat treatment temperature, heat treatment time, relaxation rate, and micro-stretching rate, the thermal shrinkage rate of the laminate is adjusted within the range of (2).

[0063] For the purpose of adjusting the thermal shrinkage rate of the laminate, relaxation may be performed during cooling after the heat treatment step, and further, micro-stretching may be performed after the heat treatment step.

[0064] In the door glass 10, the infrared reflection film 5 is arranged such that its maximum shrinkage direction substantially coincides with the vertical direction or the vehicle width direction of the door glass 10. In this case, "substantially coincides" means that the angular deviation is within ±5°.

[0065] Requirement (3) for the infrared reflection film 5 is a requirement regarding the outer peripheral position of the infrared reflection film 5 in the visible region when the laminated glass 10 is viewed from the front. Hereinafter, unless otherwise specified, the visible region is the visible region when the laminated glass 10 is viewed from the front. The same applies to the non-visible region. When the infrared reflection film 5 satisfies requirement (3), that is, the distance between the outer periphery of the infrared reflection film 5 and the outer periphery of the laminated glass 10 in the visible region is within 10 mm, the glare at the edge of the laminated glass 10 is suppressed.

[0066] Incidentally, the outer periphery of the laminated glass 10 in a front view usually coincides with the outer peripheries of the first glass plate 1 and the second glass plate 2 in a front view.

[0067] The distance between the outer periphery of the infrared reflection film 5 in the viewing area and the outer periphery of the laminated glass 10 may be set so that the maximum value is within 10 mm. Hereinafter, the distance between the outer periphery of the infrared reflection film 5 in the viewing area and the outer periphery (end face of the glass plate) of the laminated glass 10 is indicated by "distance W". When the outer peripheral positions of the first glass plate and the second glass plate are different, the outer periphery of the glass on the outer side is taken as the outer periphery of the laminated glass. For example, if the maximum value of the distance W is within 10 mm, the left side (front side), right side (rear side), and upper side of the laminated glass 10 above the belt line VL, which is the viewing area, may have different distances W from each other, and may also be different within each side. In FIG. 1, the distance w1 on the left side, the distance w2 on the right side, and the distance w3 on the upper side in the viewing area above the belt line VL are set to be the same.

[0068] Here, it is considered that the main cause of the flickering is mainly due to the end face of the infrared reflection film 5 being visible. As shown in FIG. 3, when the window is closed, none of the end faces of the door glass 10 can be seen, but when the distance W exceeds 0, depending on the vehicle type, the outer periphery of the infrared reflection film 5 may be visible in a front view. In that case, depending on the viewing angle, the end face of the infrared reflection film 5 may be visible, particularly on the left side (front side). Furthermore, as the door glass 10 moves up and down, the end face of the infrared reflection film 5 is particularly likely to be visible on the upper side.

[0069] However, in any of the above cases, if the distance W is at most 10 mm, the flickering at the end of the laminated glass is sufficiently suppressed. The distance W is preferably set such that the maximum value is within 5 mm, more preferably within 3 mm, still more preferably within 1.5 mm, and particularly preferably 0 mm. Further, depending on the vehicle type, when the window is closed or when the door glass 10 is raised or lowered, measures such as shortening the distance W may be taken with respect to the side where the end face of the infrared reflection film 5 is particularly likely to be visually recognized.

[0070] In the laminated glass 10, since the infrared reflection film 5 is made of resin, even if the distance W is 0 mm, there is almost no influence due to exposure to the outside air, and it is possible to ensure durability. Further, since the infrared reflection film 5 satisfies the requirement of (2), even if the distance W is 0 mm, there is almost no occurrence of appearance defects due to the drawing-in of the adhesive layer during the production of the laminated glass.

[0071] In the non-visible region of the laminated glass 10, the distance between the outer periphery of the infrared reflection film 5 and the outer periphery of the laminated glass 10 is not particularly limited. However, from the viewpoint of the production efficiency of the laminated glass 10, also in the left side (front side), right side (rear side), and lower side of the laminated glass 10 below the belt line VL which is the non-visible region, it is preferable that the distance between the outer periphery of the infrared reflection film 5 and the outer periphery of the laminated glass 10 is the same as the distance W in the visible region. Specifically, in the left side of the laminated glass 10 in the non-visible region, the distance is w1, in the right side, the distance is w2, and it is preferable that the distance w4 at the lower side is equivalent to these.

[0072] Regarding requirement (5), it is preferable that the infrared reflection film 5 has a minimum outer peripheral curvature radius of 8 mm or more in the visual recognition area of the laminated glass 10. In the visual recognition area of the laminated glass 10, all the corner portions of the outer periphery in a normal plan view are formed to have a curvature. Similarly, in the visual recognition area of the laminated glass 10, all the corner portions of the outer periphery of the infrared reflection film 5 in a plan view are formed to have a curvature. In the infrared reflection film 5 shown in FIG. 1, the point where the outer periphery has the minimum curvature radius is point A at the corner formed by the upper side and the right side (the rear side). In a front view, if there is a portion with a curvature radius of less than 8 mm on the outer periphery of the infrared reflection film 5, the design may be impaired because this portion sharply reflects light. The minimum outer peripheral curvature radius of the infrared reflection film 5 is preferably 10 mm or more, and more preferably 15 mm or more. [Adhesive layer] The first adhesive layer 3 and the second adhesive layer 4 in the door glass 10 have main surfaces that are the same shape and size as the main surfaces of the first glass plate 1 and the second glass plate 2, and are flat film-like layers with a thickness as described below. The first adhesive layer 3 and the second adhesive layer 4 have the function of sandwiching the infrared reflection film 5 therebetween and being inserted between the first glass plate 1 and the second glass plate 2 to bond them together to form the door glass 10 integrally.

[0073] The first adhesive layer 3 and the second adhesive layer 4 can have the same configuration except for their arrangement positions in the door glass 10. Hereinafter, the first adhesive layer 3 and the second adhesive layer 4 will be collectively described as the "adhesive layer".

[0074] The adhesive layer is composed of an adhesive layer containing a thermoplastic resin used for the adhesive layer of ordinary laminated glass. The type of the thermoplastic resin is not particularly limited, and it can be appropriately selected from the thermoplastic resins constituting known adhesive layers.

[0075] Examples of the thermoplastic resin include polyvinyl acetals such as polyvinyl butyral (PVB), polyvinyl chloride (PVC), saturated polyester, polyurethane, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer, cycloolefin polymer (COP), etc. The thermoplastic resin may be used alone or in combination of two or more kinds.

[0076] The thermoplastic resin is selected in consideration of the balance of various properties such as glass transition point, transparency, weather resistance, adhesive strength, puncture resistance, impact energy absorption, moisture resistance, heat insulation, etc. The glass transition point of the thermoplastic resin can be adjusted, for example, by the amount of plasticizer. Considering the balance of the above-mentioned various properties, PVB, EVA, polyurethane, etc. are preferable as the thermoplastic resin used for the adhesive layer. Further, PVB is particularly preferable in consideration of reducing the amount of deformation of the infrared reflection film 5 during the production of the door glass 10.

[0077] The adhesive layer contains a thermoplastic resin as a main component. That the adhesive layer contains a thermoplastic resin as a main component means that the content of the thermoplastic resin with respect to the total amount of the adhesive layer is 30% by mass or more. The adhesive layer may contain one or more kinds of various additives such as infrared absorbent, ultraviolet absorbent, fluorescent agent, adhesion adjuster, coupling agent, surfactant, antioxidant, heat stabilizer, light stabilizer, dehydrating agent, defoaming agent, antistatic agent, flame retardant, etc.

[0078] The adhesive layer preferably has a heat shrinkage rate of 2.0% or more and 8.0% or less in the direction in which the heat shrinkage rate is maximum (hereinafter, also referred to as the "maximum shrinkage direction" in the same manner as in the case of the infrared reflection film), and a heat shrinkage rate of 2.0% or more and 8.0% or less in the direction orthogonal to the maximum shrinkage direction (hereinafter, simply referred to as the "orthogonal direction" in the same manner as in the case of the infrared reflection film). The heat shrinkage rate in the maximum shrinkage direction in the adhesive layer is more preferably 4.0% or more and 7.0% or less, and the heat shrinkage rate in the orthogonal direction is more preferably 4.0% or more and 7.0% or less.

[0079] However, the thermal shrinkage rate of the adhesive layer is defined as the shrinkage rate of the length in a predetermined direction before and after heat treatment. The state before heat treatment is when the adhesive layer is left in a constant temperature and humidity environment of 20°C and 55% humidity for 24 hours or more. After that, the adhesive layer is held at 50°C for 10 minutes and then left to cool in a desiccator at 20°C for 1 hour, which is considered the state after heat treatment. Specifically, the thermal shrinkage rate of the adhesive layer can be measured in the same manner as the method for measuring the thermal shrinkage rate of the above infrared reflection film, except that the temperature and test time of the heat treatment are changed to 50°C and 10 minutes, and pretreatment and post-treatment are performed before and after the heat treatment.

[0080] Similar to the infrared reflection film 5, the adhesive layer is manufactured by stretching the constituent material into a film shape, and the residual stress is large and it is prone to thermal shrinkage in the MD direction, which is the flow direction during manufacturing. Therefore, usually, the MD direction is the maximum shrinkage direction, and the TD direction, which is the width direction, is the orthogonal direction. When the maximum shrinkage directions of the infrared reflection film 5 and the adhesive layer are aligned during the manufacture of the door glass 10, the infrared reflection film 5 is likely to be subjected to a deformation load.

[0081] Therefore, in the door glass 10, the adhesive layer is preferably arranged such that the maximum shrinkage direction of the infrared reflection film 5 is orthogonal to the maximum shrinkage direction of the adhesive layer. It is preferable that the maximum shrinkage directions of the adhesive layer and the infrared reflection film are completely orthogonal to each other, but the angular deviation from the completely orthogonal state may be within ±5° for each adhesive layer.

[0082] Also, in the door glass 10, it is preferable that the value (H) obtained by dividing the thermal shrinkage rate in the direction where the thermal shrinkage rate of the infrared reflection film 5 is maximum by the average value of the thermal shrinkage rates in the directions where the thermal shrinkage rates of the first adhesive layer 3 and the second adhesive layer 4 are maximum is in the range of 0.1 or more and 0.4 or less. When the numerical value H is 0.1 or more, the deformation load on the infrared reflection film due to the shrinkage of the adhesive layer becomes small, and appearance defects such as orange peel and wrinkles are less likely to occur. When the numerical value H is 0.4 or less, the thermal shrinkage rates of the adhesive layer and the infrared reflection film do not approach too closely in the direction where they match, the shrinkage of the infrared reflection film is not accelerated, and appearance defects caused by the infrared reflection film being pulled in are less likely to occur.

[0083] The film thicknesses of the first adhesive layer 3 and the second adhesive layer 4 are not particularly limited. Specifically, similar to the adhesive layers commonly used for automotive laminated glass and the like, it is preferably 0.3 to 0.8 mm for each, and preferably 0.7 to 1.5 mm as the total film thickness of the first adhesive layer 3 and the second adhesive layer 4. If the film thickness of each adhesive layer is less than 0.3 mm or the total film thickness of the two layers is less than 0.7 mm, the strength may be insufficient even when the two layers are combined. Conversely, if the film thickness of each adhesive layer exceeds 0.8 mm or the total film thickness of the two layers exceeds 1.5 mm, in the autoclave bonding (pressing) process for manufacturing the door glass 10 described later, a phenomenon of displacement may occur between the first glass plate 1 and the second glass plate 2 that sandwich this, that is, a so-called plate displacement phenomenon may occur.

[0084] The adhesive layer is not limited to a single-layer structure. For example, a multilayer resin film in which resin films having different properties (different loss tangents) used for improving sound insulation performance disclosed in Japanese Patent Application Laid-Open No. 2000-272936 and the like may be used as the adhesive layer. Further, in the door glass 10, the adhesive layer may be designed such that the cross-sectional shape in the vertical direction is a wedge shape. As the wedge shape, the thickness of the adhesive layer may monotonically decrease from the upper side to the lower side, or as long as the thickness of the upper side is larger than the thickness of the lower side, it may have a design with a portion where the thickness is uniform, or the wedge angle may partially change. [Glass plate] The plate thicknesses of the first glass plate 1 and the second glass plate 2 in the door glass 10 vary depending on their composition and the composition of the first adhesive layer 3 and the second adhesive layer 4, but generally are 0.1 to 10 mm.

[0085] When, for example, the first glass plate 1 is arranged on the vehicle interior side among the first glass plate 1 and the second glass plate 2, the thickness of the first glass plate 1 is preferably 0.5 to 2.0 mm, more preferably 0.7 to 1.8 mm. In that case, since the impact resistance against flying stones of the second glass plate 2 on the vehicle exterior side is good, the thickness is preferably 1.6 mm or more. The difference in thickness between the two is preferably 0.3 to 1.5 mm, more preferably 0.5 to 1.3 mm. The thickness of the second glass plate 2 on the vehicle exterior side is preferably 1.6 to 2.5 mm, more preferably 1.7 to 2.1 mm.

[0086] From the viewpoint of weight reduction, it is preferable that the total thickness of the first glass plate 1 and the second glass plate 2 is 4.1 mm or less, more preferably 3.8 mm or less, and even more preferably 3.6 mm or less.

[0087] In addition, as shown in FIG. 2, it is preferable that the end faces of the first glass plate 1 and the second glass plate 2 are chamfered. The chamfering process can be performed by a normal method. By chamfering the glass plate, it becomes practical from both the viewpoints of design and glass handling safety.

[0088] The first glass plate 1 and the second glass plate 2 can be composed of inorganic glass or organic glass (resin). Examples of inorganic glass include ordinary soda-lime glass (also referred to as soda-lime silicate glass), aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, etc. Among these, soda-lime glass is particularly preferable. Examples of inorganic glass include float plate glass formed by a float method or the like. As the inorganic glass, those subjected to strengthening treatments such as air-cooled strengthening and chemical strengthening can also be used.

[0089] Examples of the organic glass (resin) include polycarbonate resin, polystyrene resin, aromatic polyester resin, acrylic resin, polyester resin, polyarylate resin, polycondensate of halogenated bisphenol A and ethylene glycol, acrylic urethane resin, acrylic resin containing a halogenated aryl group, and the like. Among these, polycarbonate resins such as aromatic polycarbonate resin and acrylic resins such as polymethyl methacrylate-based acrylic resin are preferred, and polycarbonate resin is more preferred. Further, among the polycarbonate resins, bisphenol A-based polycarbonate resin is particularly preferred. Note that two or more of the above resins may be used in combination.

[0090] The glass may contain an infrared absorber, an ultraviolet absorber, and the like. Examples of such glass include green glass, ultraviolet absorption (UV) green glass, and the like. Note that the UV green glass contains 68% by mass or more and 74% by mass or less of SiO2, 0.3% by mass or more and 1.0% by mass or less of Fe2O3, and 0.05% by mass or more and 0.5% by mass or less of FeO, and has an ultraviolet transmittance of 1.5% or less at a wavelength of 350 nm and a minimum transmittance value in the region of 550 nm or more and 1700 nm or less.

[0091] The glass only needs to be transparent and may be colorless or colored. Further, the glass may be a laminate of two or more layers. Depending on the application location, inorganic glass is preferred.

[0092] The materials of the first glass plate 1 and the second glass plate 2 may be the same or different, but it is preferable that they are the same. The shapes of the first glass plate 1 and the second glass plate 2 may be flat plates or may have a curvature on the entire surface or a part thereof. A coating that imparts a water repellent function, a hydrophilic function, an anti-fogging function, or the like may be applied to the surfaces of the first glass plate 1 and the second glass plate 2 that are exposed to the atmosphere. Further, a coating that usually includes a metal layer, such as a low-emissivity coating, an infrared light shielding coating, or a conductive coating, may be applied to the opposing surfaces of the first glass plate 1 and the second glass plate 2. [Laminated glass] The laminated glass constituting the door glass of the present invention preferably has a visible light reflectance of 7% or more and 10% or less on the outside of the vehicle.

[0093] When the visible light reflectance (Rv) measured from the outside of the vehicle of the laminated glass 10 is less than 7%, the function of the infrared reflection film 5 may not be sufficient, that is, the heat insulation property may not be sufficient. When the visible light reflectance (Rv) exceeds 10%, the glare caused by the end face of the infrared reflection film tends to be conspicuous at the end of the laminated glass. The visible light reflectance (Rv) is more preferably 7.5% or more and 10.0% or less.

[0094] The laminated glass 10 preferably has a solar transmittance (Te) of 45% or less and a visible light transmittance (Tv) of 70% or more. The solar transmittance (Te) is more preferably 40% or less, and particularly preferably 38% or less. The solar reflectance (Re) measured from the outside of the vehicle is more preferably 18% or more, and particularly preferably 20% or more. The visible light transmittance (Tv) is more preferably 72% or more, and particularly preferably 73% or more. Further, the haze value of the laminated glass 10 is preferably 1.0% or less, more preferably 0.8% or less, and particularly preferably 0.6% or less.

[0095] The visible light reflectance (Rv) measured from the outside of the vehicle, the solar reflectance (Re) measured from the outside of the vehicle, the solar transmittance (Te), and the visible light transmittance (Tv) are values calculated from the calculation formulas specified in JIS R3106 (1998) and JIS R3212 (1998) by measuring the transmittance and reflectance in the wavelength range including at least 300 to 2100 nm with a spectrophotometer or the like. In this specification, unless otherwise specified, the visible light reflectance, the solar reflectance, the solar transmittance, and the visible light transmittance refer to the visible light reflectance (Rv) measured from the outside of the vehicle, the solar reflectance (Re) measured from the outside of the vehicle, the solar transmittance (Te), and the visible light transmittance (Tv) measured and calculated by the above method.

[0096] Furthermore, for the laminated glass 10, the color tone of the reflected light obtained by irradiating light from a D65 light source from the outside of the vehicle in the range of an incident angle of 10 to 60° is CIE1976L* a * b * In chromaticity coordinates, -5 < a * < 3 and -12 < b * < 2 is preferable. When the values of a * and b * measured under the above conditions are outside the above ranges, the glare caused by the end face of the infrared reflection film at the edge of the laminated glass tends to be prominent. a * is preferably -3 < a * < 2. b * measured under the above conditions is preferably -9 < b * < 0. [Manufacture of door glass] The door glass of the present invention can be manufactured by a generally used known technique. In the door glass (laminated glass) 10, a laminated glass precursor before crimping is prepared in which the first glass plate, the first adhesive layer, the infrared reflection film, the second adhesive layer, and the second glass plate prepared as described above are laminated in that order. At this time, the above components are laminated so that the positional relationship between the outer periphery of the obtained laminated glass and the outer periphery of the infrared reflection film in a front view satisfies the requirement of (3). Further, if necessary, the TD direction and the MD direction of the first adhesive layer, the infrared reflection film, and the second adhesive layer are laminated so as to be in the above preferable directions.

[0097] This laminated glass precursor is placed in a vacuum bag such as a rubber bag, the vacuum bag is connected to an exhaust system, and the pressure in the vacuum bag is reduced to about -65 to -100 kPa (absolute pressure of about 36 to 1 kPa) while heating to a temperature of about 70 to 110 °C with vacuum suction (degassing). As a result, a laminated glass in which the first glass plate, the first adhesive layer, the infrared reflection film, the second adhesive layer, and the second glass plate are all adhered is obtained. Then, if necessary, the laminated glass is placed in an autoclave and subjected to a crimping treatment of heating and pressurizing under the conditions of a temperature of about 120 to 150 °C and a pressure of about 0.98 to 1.47 MPa. The durability of the laminated glass can be further improved by the crimping treatment.

Example

[0098] The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the examples described below. First, nine types of infrared reflection films A to I were manufactured by the following method. Infrared reflection films A to H are each a laminate obtained by laminating two resin layers having different refractive indices, and are infrared reflection films having different thermal shrinkage rates. Infrared reflection film I is an infrared reflection film in which two inorganic oxide layers having different refractive indices are laminated on a PET film. (Manufacture of Infrared Reflection Films A to H) As two types of thermoplastic resins having different refractive indices, resin A and resin B were used. As resin A, PET (crystalline polyester, melting point 255°C) having an intrinsic viscosity IV = 0.65 and a refractive index of 1.66 was used. As resin B, a PET copolymer (PE / SPG·T / CHDC) containing 25 mol% of spiroglycol units and 30 mol% of cyclohexanedicarboxylic acid units with respect to all units, having an intrinsic viscosity IV = 0.73 and a refractive index of 1.55, was used. The two prepared resins were each melted at 280°C in an extruder, and 2000 layers were alternately laminated in the thickness direction so that the optical thickness ratio of resin A / resin B = 1 to obtain an unstretched laminate.

[0099] In infrared reflection films A to H, the unstretched laminate was biaxially stretched at a predetermined magnification, the thickness of the laminate was adjusted, and then heat treatment was performed to adjust the residual stress (thermal shrinkage rate) in the MD direction and the TD direction, thereby obtaining infrared reflection films having the physical properties (thermal shrinkage rate, thickness) shown in Table 1. The thermal shrinkage rate shown in Table 1 has the "maximum direction" corresponding to the direction in which the thermal shrinkage rate is the largest, specifically, the MD direction of the infrared reflection film. The "orthogonal direction" shown in Table 1 is the direction orthogonal to the "maximum direction", which is the TD direction of the infrared reflection film. Note that the thermal shrinkage rate of the infrared reflection film is the reduction rate of the length in a predetermined direction before and after holding the infrared reflection film at 150°C for 30 minutes, and is the value measured by the above method. (Manufacture of Infrared Reflection Film I) On a PET film with a thickness of 100 μm, a Nb2O5 layer serving as a high refractive index dielectric layer and a SiO2 layer serving as a low refractive index dielectric layer were alternately laminated in that order for 7 layers by the magnetron sputtering method to form an infrared reflective film, which was designated as infrared reflective film I. [Examples 1 to 14] It has the same laminated structure as the laminated glass shown in FIG. 2, with w1 = w2, and laminated glass with different w1 (w2) in each example was manufactured and evaluated as follows. Examples 1 to 8 are examples, and examples 9 to 14 are comparative examples. (Manufacture of laminated glass) As the first glass plate, a heat ray absorbing green glass (manufactured by Asahi Glass Co., Ltd.: NHI (common name)) with an outer peripheral size of 500 mm in length and 950 mm in width and a plate thickness of 2 mm when viewed from the front of the glass plate was prepared. As the second glass plate, a clear glass (manufactured by Asahi Glass Co., Ltd.: FL (common name)) with an outer peripheral size of 500 mm in length and 950 mm in width and a plate thickness of 2 mm when viewed from the front was prepared.

[0100] For the first adhesive layer, a PVB film with a thickness of 0.76 mm (manufactured by Eastman Chemical Company: product number QL51) was used. For the second adhesive layer, a PVB film with a thickness of 0.38 mm (manufactured by Eastman Chemical Company: product number RK11) was used, and their outer peripheral sizes were the same as those of the first glass plate and the second glass plate, 500 mm in length and 950 mm in width. In the case of the two types of PVB films with different thicknesses, the heat shrinkage rates in the direction where the heat shrinkage rate is maximum, specifically the heat shrinkage rate in the MD direction, were both 6.0%, and the heat shrinkage rates in the direction orthogonal to it, specifically the heat shrinkage rate in the TD direction, were both 5.0%. Also, the heat shrinkage rate of the PVB film is the value measured by the above method for the PVB film. Furthermore, by adjusting the stretching method, two types of adhesive layers with heat shrinkage rates different from the above were prepared. In both cases, the first adhesive layer was a PVB film with a thickness of 0.76 mm, and the second adhesive layer was a PVB film with a thickness of 0.38 mm. For one adhesive layer, the heat shrinkage rate in the MD direction was 8.5% and the heat shrinkage rate in the TD direction was 7.0%. For the other adhesive layer, the heat shrinkage rate in the MD direction was 2.5% and the heat shrinkage rate in the TD direction was 2.0%.

[0101] In each example, a laminate was prepared by laminating a first glass plate, a first adhesive layer, an infrared reflection film, a second adhesive layer, and a second glass plate in that order, using any one of the infrared reflection films A to I obtained above.

[0102] In each example, the size of the infrared reflection films A to I was adjusted so that the distance (w1) between the outer periphery of the infrared reflection films A to I in the front view and the outer peripheries of the first glass plate and the second glass plate was the value shown in Table 1 on all four sides in advance. Further, the first adhesive layer, the infrared reflection film, and the second adhesive layer were all laminated with the MD direction aligned with the lateral direction of the first glass plate and the second glass plate.

[0103] The laminate was placed in a vacuum bag, degassed so that the display of the pressure gauge became 100 kPa or less, then heated to 120 °C and pressure-bonded, and further heated and pressurized at a temperature of 135 °C and a pressure of 1.3 MPa for 60 minutes in an autoclave, and finally cooled to obtain laminated glass.

[0104] In the laminated glass obtained in each example, the visible light reflectance (Rv), the solar reflectance (Re), and the CIE1976L * a * b * chromaticity coordinates of a * and b * were measured. A spectrophotometer (U4100 manufactured by Hitachi High-Technologies) was used for the measurement. The results are shown in Table 1. [Evaluation] For the obtained laminated glass, deterioration at the end of the infrared reflection film, retraction of the adhesive layer, glitter, orange peel, and heat insulation performance were evaluated. <Deterioration at the end of the infrared reflection film> The laminated glass was placed in a thermo-hygrostat at a temperature of 80 °C and a humidity of 95% RH, and after 1000 hours, the presence or absence of discoloration at the end of the infrared reflection film was visually observed. In addition, the presence or absence of cracks in the range within 20 mm from the outer periphery of the infrared reflection film was confirmed by microscopic observation. The evaluation was carried out according to the following criteria. A; No discoloration or crack is observed at the edge of the infrared reflection film. C; Discoloration or crack is observed at the edge of the infrared reflection film. <Adhesive layer draw-in> When viewed from the front, it was visually observed whether the outer periphery of the adhesive layer and the outer periphery of the infrared reflection film were drawn inwards from the outer periphery of the laminated glass and from the position in the laminate before crimping. The evaluation was carried out according to the following criteria. A; No draw-in of either the infrared reflection film or the adhesive layer is observed. C; A portion where the outer peripheries of the adhesive layer and the infrared reflection film are drawn in over a length of 5 mm or more is observed.

[0105] The value obtained by dividing the heat shrinkage rate in the direction in which the heat shrinkage rate of the infrared reflection film is maximum by the average value of the heat shrinkage rates in the directions in which the heat shrinkage rates of the first adhesive layer and the second adhesive layer are maximum was calculated as the "heat shrinkage ratio (H)", and the results are summarized in Table 1. <Glitter; Color tone change> With the laminated glass as the door glass, for example, with the vehicle assembled as shown in Fig. 3, the glitter (color tone change) at the edge of the door glass was visually observed from inside the vehicle. The laminated glass had the shape shown in Fig. 1. The evaluation was carried out according to the following criteria. A; No change in the color tone at the edge of the door glass is observed regardless of the raising and lowering of the door glass. B; A change in the color tone at the edge of the door glass is observed only when the door glass is raised and lowered (during operation). C; A change in the color tone at the edge of the door glass is observed regardless of the raising and lowering of the door glass. <Orange peel> The bonding glass was placed horizontally with the background darkened, and a straight fluorescent lamp (length 630 mm, 30 W, FL30SW manufactured by Mitsubishi Electric Lighting Co., Ltd.) was installed 180 cm above the bonding glass so that the length direction was the width direction of the bonding glass and lit. The position of the fluorescent lamp was adjusted so that it was directly above the central part of the bonding glass, and the presence or absence of fluctuation in the contour of the reflected image of the fluorescent lamp at the central part was visually observed. Similarly, the position of the fluorescent lamp was adjusted so that it was directly above the vicinity of the lower edge of the bonding glass, and the presence or absence of fluctuation in the contour of the reflected image of the fluorescent lamp in the vicinity of the lower edge was visually observed. The observation results were evaluated according to the following criteria. A; No fluctuation is observed in the contour of the reflected image of the fluorescent lamp. B; Fluctuation is observed in a part of the contour of the reflected image of the fluorescent lamp in the central part or the vicinity of the lower edge. C; Fluctuation is observed in about half of the contour of the reflected image of the fluorescent lamp in the central part and the vicinity of the lower edge. <Heat insulation property> The solar reflectance Re of the bonding glass measured above was used as an index for heat insulation property evaluation. The solar reflectance Re was all 20% or more, which was good. <Design property of the door glass corner> Bonding glasses having the shape in the front view shown in Fig. 1 were prepared. A total of three types of bonding glasses were prepared in which the curvature radii of the infrared reflection films at point A where the outer periphery has the minimum curvature radius were 16 mm, 9 mm, and 7 mm, respectively. For the bonding glasses with curvature radii of 16 mm and 9 mm at point A, the infrared reflection film of Example 2 was used, and for the bonding glass with a curvature radius of 7 mm at point A, the infrared reflection film of Example 3 was used. The bonding glass was placed under the fluorescent lamp, and the appearance of the infrared reflection film at point A was visually observed. As a result, when the curvature radius of point A was 16 mm or 9 mm, no strong light reflection was observed and the design property was at a level without problems. On the other hand, when the curvature radius of point A was 7 mm, strong light reflection was observed and the design property was poor.

[0106]

Table 1

Description of Reference Numerals

[0107] 10 Laminated glass (vehicle door glass) 1 First glass plate 2 Second glass plate 3 First adhesive layer 4 Second adhesive layer 5 Infrared reflection film 100 Automobile 20 Door panel VL Belt line

Claims

1. A vehicle door glass including a laminated glass in which a first glass plate, a first adhesive layer, an infrared reflection film, a second adhesive layer, and a second glass plate are laminated in this order, The infrared reflection film includes a laminate in which 100 or more resin layers having different refractive indexes are laminated, The infrared reflection film has a thermal shrinkage rate in the direction where the thermal shrinkage rate is maximum exceeding 0.6% and less than 1.2%, and a thermal shrinkage rate in the direction orthogonal to the direction exceeding 0.6% and less than 1.2%. The thermal shrinkage rate of the infrared reflection film in a predetermined direction is the reduction rate of the length in the predetermined direction before and after holding the infrared reflection film at 150° C. for 30 minutes, When the laminated glass is attached to a vehicle, in a region where the laminated glass is visible in a front view, the outer periphery of the infrared reflection film is located within a range of 10 mm inward from the outer periphery of the laminated glass in the front view, The visible light reflectance measured from the outside of the vehicle of the laminated glass is 7% or more and 10% or less, The solar reflectance measured from the outside of the vehicle of the laminated glass is 20% or more, characterized in that it is a vehicle door glass.

2. For the laminated glass, the color tone of the reflected light obtained by irradiating light from a D65 light source from the outside of the vehicle within an incident angle range of 10 to 60° is CIE1976L ＊ a ＊ b ＊ chromaticity coordinates, -5 < a ＊ < 3 and -12 < b ＊ < 2, the vehicle door glass according to claim 1.

3. When the laminated glass is attached to a vehicle, in a region where the laminated glass is visible, the outer periphery of the infrared reflection film is arranged to be located within a range of 5 mm inward from the outer periphery of the laminated glass in the front view, the vehicle door glass according to claim 1 or 2.

4. When the laminated glass is attached to a vehicle, in the visible region of the laminated glass, all corners of the outer periphery of the infrared reflection film have curvature in a front view, and the minimum radius of curvature of the outer periphery is 8 mm or more. The vehicle door glass according to any one of claims 1 to 3.

5. The vehicle door glass according to any one of claims 1 to 4, wherein the thickness of the infrared reflection film is 120 μm or less.

6. The infrared reflection film is formed by alternately laminating two resin layers having different refractive indexes, and the resin constituting the resin layer contains at least one selected from polyethylene terephthalate and polyethylene terephthalate copolymer. The vehicle door glass according to any one of claims 1 to 5.

7. The first adhesive layer and the second adhesive layer have a heat shrinkage rate in the direction of maximum heat shrinkage rate of 2% or more and 8% or less, and a heat shrinkage rate in the direction orthogonal to the direction of 2% or more and 8% or less. The heat shrinkage rate of the first adhesive layer and the second adhesive layer in a predetermined direction is the shrinkage rate of the length in the predetermined direction before and after holding the first adhesive layer and the second adhesive layer at 50 ° C for 10 minutes. The vehicle door glass according to any one of claims 1 to 6, wherein the direction in which the heat shrinkage rate of the infrared reflection film is maximum and the direction in which the heat shrinkage rate of the first adhesive layer and the second adhesive layer is maximum are orthogonal to each other.

8. The first adhesive layer and the second adhesive layer contain polyvinyl butyral. The vehicle door glass according to any one of claims 1 to 7.

9. The value obtained by dividing the heat shrinkage rate in the direction in which the heat shrinkage rate of the infrared reflection film is maximum by the average value of the heat shrinkage rates in the direction in which the heat shrinkage rates of the first adhesive layer and the second adhesive layer are maximum is in the range of 0.1 or more and 0.4 or less. The vehicle door glass according to any one of claims 1 to 8.

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