CN115782323A

CN115782323A - Glass laminate

Info

Publication number: CN115782323A
Application number: CN202211572310.1A
Authority: CN
Inventors: 佐佐木辉幸
Original assignee: Nippon Sheet Glass Co Ltd
Current assignee: Nippon Sheet Glass Co Ltd
Priority date: 2018-03-06
Filing date: 2019-03-06
Publication date: 2023-03-14
Also published as: JP7153455B2; JP2022186747A; JP2019151538A; WO2019172313A1; CN111819160B; CN111819160A

Abstract

The glass laminate is a glass laminate to be mounted on a vehicle, and has a glass body including at least 1 glass plate and an ultraviolet blocking film disposed on at least 1 of the glass plates, wherein the glass body satisfies Tuv 400. Ltoreq.50%, the glass laminate has a transmittance of light having a wavelength of 400nm of 10% or less, and the glass laminate satisfies Tuv 400. Ltoreq.2.0%.

Description

Glass laminate

The application date of the present case is2019, 3 and 6 monthsApplication number of 201980017186.2

(PCT/JP2019/008877)The invention is a divisional application of a glass laminate.

Technical Field

The present invention relates to a glass laminate to be mounted on a vehicle.

Background

Windshields and side windows for mounting on vehicles are required to transmit visible light and to have a function of blocking ultraviolet rays from the viewpoint of sun protection. As such glass, for example, as described in patent document 1, an ultraviolet ray blocking film is laminated on a glass plate to improve the ultraviolet ray blocking function.

Documents of the prior art

Patent literature

Patent document 1: japanese patent No. 5396265

Disclosure of Invention

Technical problem to be solved by the invention

However, there is room for improvement in the ultraviolet ray blocking function, and glasses having a higher ultraviolet ray blocking function are demanded. The invention aims to provide a glass laminate for a vehicle having a high ultraviolet blocking function.

Means for solving the problems

The glass laminate for mounting on a vehicle, comprising a glass body including at least 1 glass plate and an ultraviolet ray blocking film disposed on at least 1 of the glass plates, wherein the glass body satisfies Tuv 400. Ltoreq.50%, the glass laminate has a transmittance of light having a wavelength of 400nm of 10% or less, and the glass laminate satisfies Tuv 400. Ltoreq.2.0%.

The glass laminate according to item 1, wherein the glass laminate has a transmittance of 20% or more for light having a wavelength of 420 nm.

Item 3 the glass laminate according to

item

1 or 2, wherein when Tavg is an average value of transmittances of light of 420 to 800nm in wavelength of the glass body, a difference between a wavelength of light of Tavg × 0.9 in transmittance of the glass body and a wavelength of light of Tavg × 0.1 in transmittance of the glass body is 20 to 50nm.

Item 4 is the glass laminate according to item 3, wherein when Tavg is an average value of transmittances of light of 420 to 800nm in wavelength of the glass laminate, a difference between a wavelength of light of Tavg × 0.9 in transmittance of the glass laminate and a wavelength of light of Tavg × 0.1 in transmittance of the glass laminate is 22nm or less.

The glass laminate according to any one of items 1 to 4, wherein the glass laminate has a thickness in accordance with JIS T7330: the blue light reduction rate of 2000 is 35% or more.

Item 6 is the glass laminate according to any one of items 1 to 5, wherein the glass laminate is one that is obtained by laminating a glass sheet according to JIS K7373: the yellow index YI of 2006 is 5 or less.

Item 7 the glass laminate according to any one of items 1 to 6, wherein the glass laminate has a thickness in accordance with JIS K7373: the yellow index YI of 2006 is 10 or less.

The glass laminate according to any one of claims 1 to 7, wherein the glass laminate has a transmittance of 85% or less for light having a wavelength of 420 nm.

The glass laminate according to any one of claims 1 to 8, which is attached to a vehicle door as a sash window.

The glass laminate according to any one of the above 1 to 8, which is used for a windshield.

The glass laminate according to any one of claims 1 to 10, wherein the glass body comprises a first glass plate, a second glass plate, and an interlayer film disposed between the first glass plate and the second glass plate.

The glass laminate according to any one of claims 1 to 11, wherein the glass body further comprises a base sheet and an adhesive disposed between one of the glass plates and the base sheet and adhering the base sheet to the glass plate, and the ultraviolet blocking film is formed on a surface of the base sheet opposite to the adhesive.

The glass laminate according to any one of claims 1 to 12, wherein the glass body has a thickness of 2mm or more.

Item 14. The glass laminate according to any one of items 1 to 13, wherein an amount of 3-valent iron oxide contained per unit area of the glass body is converted into Fe ₂ O ₃ Is 1 to 10mg/cm ² 。

The glass laminate according to any one of claims 1 to 13, wherein the glass body has a visible light transmittance YA of 70% or more as measured with a CIE standard illuminant a.

The glass laminate according to any one of claims 1 to 13, wherein an amount of the iron oxide having a valence of 3 contained per unit area of the glass body is converted into Fe ₂ O ₃ Is 4 to 15mg/cm ² 。

The glass laminate according to any one of claims 1 to 13, wherein the glass body has a visible light transmittance YA of 15 to 60% as measured by a CIE standard illuminant a.

The glass laminate according to any one of claims 1 to 17, wherein at least 1 of the glass sheets included in the glass body has a surface compressive stress of less than 20MPa.

The glass laminate according to any one of claims 1 to 18, wherein at least 1 of the glass sheets included in the glass body has a surface compressive stress of 80MPa or more.

The glass laminate according to any one of claims 1 to 18, wherein a surface compressive stress of all the glass plates included in the glass body is 80MPa or more.

Item 21 is the glass laminate of any one of items 1 to 20, wherein the ultraviolet blocking film is not peeled off after a TABER abrasion test is performed 1000 times under a 500g load in accordance with JIS R3221 on the surface of the glass laminate on which the ultraviolet blocking film is formed, and the haze of the glass laminate after the test is 5% or less.

The glass laminate of any of claims 1 to 20, wherein the glass laminate is irradiated with light having a wavelength of 295 to 450nm and an illuminance of 76mW/cm from a surface of the glass laminate opposite to the surface on which the ultraviolet blocking film is formed ² The difference between Tuv400 after the irradiation of the ultraviolet ray and Tuv400 before the irradiation of the ultraviolet ray is 2% or less when the ultraviolet ray of (2) is used for 100 hours.

Item 23. The glass laminate according to any one of items 1 to 22, wherein regarding a film thickness of the ultraviolet blocking film in a region excluding the ultraviolet blocking film in a range of 20mm in width from a peripheral edge, the film thickness on a lower portion side of the vehicle is thicker than the film thickness on an upper portion side of the vehicle, and a maximum value of the film thickness is 0.5 to 10 μm.

Item 24. The glass laminate according to any one of items 1 to 23, wherein regarding a film thickness of the ultraviolet blocking film in a region excluding the ultraviolet blocking film in a range of 20mm in width from a peripheral edge, a position where the film thickness is the largest is 10cm or more from the peripheral edge of the film thickness, and the maximum value of the film thickness is 0.5 to 10 μm.

The glass laminate of item 23 or 24, wherein the ultraviolet blocking film has a thickness uniformity of 70% or less.

The glass laminate according to any one of claims 1 to 25, wherein at least 1 of the glass sheets included in the glass body contains a tin component on a first main surface and a second main surface of the glass sheet, and the first main surface and the second main surface have different tin component concentrations.

The glass laminate according to any one of claims 1 to 26, wherein a mark is formed on a surface of the glass sheet exposed to the outside of the glass laminate, and the mark is formed of a rough surface portion having a surface roughness Ra of 1.5 μm.

The glass laminate according to any one of claims 1 to 27, wherein an end surface of the glass plate included in the glass body is formed in an arc shape convex outward.

The glass laminate according to any one of claims 1 to 27, wherein end faces of the glass plates included in the glass body are formed by connecting 3 or more flat surfaces, and an angle formed by the adjacent flat surfaces is an obtuse angle.

The glass laminate of any of claims 1 to 29, wherein the ultraviolet blocking film further has an antifogging property.

Item 31 the glass laminate of item 30, wherein the ultraviolet blocking film further has water absorbing properties.

The glass laminate of item 30, wherein the surface of the ultraviolet blocking film is hydrophilic.

The glass laminate of item 33, wherein the ultraviolet blocking film further has visibility-securing properties.

The glass laminate of claim 33, wherein the surface of the ultraviolet blocking film has water repellency.

The glass laminate according to any one of claims 1 to 29, further comprising a film for ensuring visibility.

The glass laminate of claim 36, wherein the visibility-securing film is disposed on a surface of the ultraviolet-blocking film opposite to the glass body.

The glass laminate of item 37, wherein the glass body comprises a first glass plate, a second glass plate, and an intermediate film disposed between the first glass plate and the second glass plate, the ultraviolet blocking film is disposed on at least one of the first glass plate and the second glass plate, and the visibility-securing film is disposed on a side of the first glass body and the second glass body opposite to a surface on which the ultraviolet blocking film is disposed.

The glass laminate according to any one of claims 1 to 37, further comprising a low reflection film.

Effects of the invention

According to the present invention, a high ultraviolet blocking function can be achieved.

Drawings

FIG. 1 is a cross-sectional view of a glass laminate according to the present invention.

Fig. 2 is a diagram illustrating sharp cutoff (sharp cut).

Fig. 3 is a sectional view illustrating the shape of the end face of the glass body.

Fig. 4 is a sectional view illustrating the shape of the end face of the glass body.

Fig. 5 is a cross-sectional view of a laminated glass.

FIG. 6 is a cross-sectional view of another example of the laminated glass.

Fig. 7 is a graph showing the transmittance of light of each wavelength of the glass body.

Fig. 8 is a graph showing the transmittance of light of each wavelength of the glass laminate.

Description of the symbols

1: a glass body; 2: an ultraviolet ray blocking film.

Detailed Description

The following describes a glass laminate mounted on a vehicle according to the present invention with reference to the drawings. As shown in fig. 1, the glass laminate includes a glass body 1 and an ultraviolet ray blocking film 2 formed on the entire surface thereof. The glass laminate is used in a vehicle, for example, for a front window (windshield), a front sash, a rear window, a fixed side window, and the like. Among them, glass for a driver to observe the outside, such as a front window glass and a front door glass, is required to have high transparency. Further, the glass does not require high transparency as in the case of a windshield glass, and may be colored. These glass body and ultraviolet blocking film will be described in detail below.

< 1. Vitreous body >

The glass body may be formed of one glass plate, or may be formed of a laminated glass in which 2 glass plates are laminated with an interlayer film interposed therebetween. In addition, hereinafter, in the case of a glass body, for example, in the case of a glass body composed of one glass plate, physical properties and the like of one glass plate are expressed; when the glass body is a laminated glass, the physical properties of the laminated glass are shown. In many cases, the windshield is formed of laminated glass, and the other side glass is formed of a single glass plate. However, glasses other than the windshield glass may be formed of laminated glass. The glass plate constituting the glass body may be a known glass plate, and may be formed of privacy glass, transparent glass, green glass, or UV green glass. The following describes a glass plate used for the glass body.

< 1-1. Thickness >

When the glass body is made of a laminated glass, the thickness of the outer glass plate may be the same as or different from that of the inner glass plate. The outer glass plate is required to have durability and impact resistance mainly against obstacles from the outside, and therefore, the thickness thereof is preferably 1.8mm or more, 1.9mm or more, 2.0mm or more, 2.1mm or more, and 2.2mm or more in this order. The upper limit of the thickness of the outer glass plate is preferably 5.0mm or less, 4.0mm or less, 3.1mm or less, 2.5mm or less, and 2.4mm or less in this order. Among them, it is preferably larger than 2.1mm and 2.5mm or less, and particularly preferably 2.2mm to 2.4 mm.

On the other hand, the thickness of the inner glass plate is preferably smaller than that of the outer glass plate 11 in order to reduce the weight of the laminated glass 1. Specifically, the thickness of the inner glass plate 12 is preferably 0.6mm or more, 0.8mm or more, 1.0mm or more, and 1.3mm or more in this order. The upper limit of the thickness of the inner glass plate 12 is preferably 1.8mm or less, 1.6mm or less, 1.4mm or less, 1.3mm or less, and less than 1.1mm in this order. Among them, for example, 0.6mm or more and less than 1.1mm are preferable.

When the glass body is formed of a single glass plate, the thickness thereof may be set to 0.6 to 5.0mm, and the thickness ranges shown in the outer glass plate and the inner glass plate described above may be appropriately adopted.

< 1-2. Composition >

The composition of the glass sheet is not particularly limited. Preference is given to using compounds having an increased Fe content ₂ O ₃ And TiO is added as required ₂ 、CeO ₂ And other ultraviolet absorbing components. This can improve the ultraviolet blocking performance.

Since transparency is required for glass sheets used for windshield glass (windshield glass), front door, and the like, the amount of 3-valent iron oxide contained per unit area is converted to Fe ₂ O ₃ Expressed as 1 to 10g/cm ² . In particular, the lower limit is preferably 2mg, more preferably 3mg. On the other hand, the upper limit is preferably 8mg, more preferably 6mg, and particularly preferably 5mg.

In contrast, a glass plate used for a rear window, a back door, or the like does not require transparency as in the above-described front window. Further, it is sometimes necessary to ensure visibility from inside to outside of the vehicle and to make it difficult to see privacy of the conditions inside the vehicle from outside of the vehicle. Therefore, in the glass sheet for such use, the amount of the 3-valent iron oxide contained per unit area is converted into Fe ₂ O ₃ Can represent 4 to 15g/cm ² . In particular, the lower limit is preferably 6mg, more preferably 8mg. On the other hand, the upper limit is preferably 12mg, more preferably 10mg. The amount of the above iron oxide having a valence of 3 is an amount per unit area, and the same applies to the laminated glass.

The glass sheet may be formed by the well-known float process. In this method, molten glass is continuously supplied onto molten metal such as molten tin, and the supplied molten glass is made to flow over the molten metal to be molded into a band plate shape. The glass thus formed is referred to as a glass ribbon. Then, the glass ribbon goes downstream and is cooled, and after being cooled and solidified, it floats from the molten metal. Then, the sheet was cut after slow cooling. Thereby obtaining a glass plate. In the float glass sheet, the surface in contact with the molten metal is referred to as a bottom surface, and the surface opposite thereto is referred to as a top surface. The bottom and top surfaces may be non-abrasive surfaces. In addition, the bottom surface is in contact with the molten metal, and thus, in the case where the molten metal is tin, the concentration of tin oxide contained in the bottom surface is greater than the concentration of tin oxide contained in the top surface.

< 1-3. Optical characteristics >

The optical properties of the glass body are as follows.

(1-3-1) ultraviolet transmittance

The ultraviolet transmittance of the glass body of the present invention is as follows.

Tuv400≤50％ (1)

Wherein Tuv400 is ISO13837:2008 standard A, ultraviolet transmittance. The ultraviolet transmittance can be measured by using a known spectrophotometer, for example, "UV-3100PC" (manufactured by Shimadzu corporation). Further, tuv400 in the above formula (1) is preferably 40% or less, more preferably 30% or less, and particularly preferably 10% or less.

(1-3-2) visible light transmittance 1

In the glass body of the present invention, when Tavg is an average value of the transmittances for light having wavelengths of 420 to 800nm, it is preferable that a difference between a wavelength W1 having a transmittance of Tavg × 0.9 and a wavelength W2 having a transmittance of Tavg × 0.1 is 20 to 50nm. Tavg can be calculated as an arithmetic average of transmittance per 1nm wavelength. In this regard, tavg, which will be described later, of the glass laminate is also the same.

When the transmittance of the glass body is at least 2 wavelengths that are Tavg × 0.9, W1 represents the shortest wavelength among the wavelengths. Similarly, when Tavg × 0.1 is 2 or more, the longest wavelength is W2.

When the transmittance of light (visible light) having a wavelength of 420 to 800nm is substantially high, for example, more than 500nm, a certain degree of transmittance can be ensured. Therefore, a small difference between the wavelength W1 corresponding to Tavg × 0.9 and the wavelength W2 corresponding to Tavg × 0.1 means that, for example, as shown in fig. 2, the transmittance sharply increases when the light enters the visible light region from the ultraviolet region. In particular, in the present invention, since the difference in wavelength (hereinafter referred to as sharp cutoff) is as low as 20 to 50nm, the transmittance in the ultraviolet region is low, and a sufficient ultraviolet blocking function can be exhibited, and when the light enters the visible light region, the transmittance rapidly increases, and thus, coloration or the like that obstructs the field of view in the glass body is reduced.

(1-3-3) visible light transmittance 2

Among the glass bodies according to the present invention, the glass body used for the glass having high transparency such as the windshield glass described above preferably has a visible light transmittance YA of 70% or more as measured using a CIE standard illuminant a.

On the other hand, in the glass sheet used for the glass that does not require high transparency, such as the above-mentioned lift glass for a rear door, the visible light transmittance YA measured using the CIE standard a light source is preferably 15 to 60%.

(1-3-4) near Infrared ray transmittance

The glass body of the present invention preferably has a transmittance of light having a wavelength of 1500nm of 35% or less, more preferably 30% or less, and particularly preferably 25% or less.

Light having a wavelength of 1500nm is light in the near infrared region, particularly in the near infrared region of sunlight. If the transmittance of such light is 35% or less as described above, near infrared rays of sunlight can be appropriately shielded, and when the glass body is used as an automobile window glass, the case where the temperature in the automobile is excessively high can be alleviated.

(1-3-5) yellow index

In the glass plate of the present invention, with respect to transmitted light from a C light source based on the CIE standard, JIS K7373: the yellowness index YI defined in 2006 preferably satisfies the following formula (2). This can reduce the yellow index of the glass plate and improve visibility.

YI≤5 (2)

Intensity of < 1-4 >

The strength of the glass sheet of the present invention is preferably set as follows. For example, as the unreinforced glass which is not subjected to the strengthening treatment such as the thermal strengthening treatment or the chemical strengthening treatment, a glass plate having a surface compressive stress of less than 20MPa is preferably used. On the other hand, as the strengthened glass to be strengthened, a glass plate having a surface compressive stress of 80MPa or more is preferably used. In the laminated glass having a plurality of glass plates, the surface compressive stress of at least one glass plate is preferably 80MPa or more, but the surface compressive stress of all the glass plates may be 80MPa or more. Further, the surface compressive stress of one glass plate may be less than 20MPa, and the surface compressive stress of the other glass plate may be 80MPa or more.

In general, the ultraviolet ray blocking function of the tempered glass is improved as compared with that of the non-tempered glass. Therefore, in the tempered glass, for example, the ultraviolet blocking film described later may be reduced in thickness, and the ultraviolet blocking function may be reduced by the film. This contributes to cost reduction. On the other hand, even in the case of the non-strengthened glass, if the ultraviolet blocking film is adjusted to be thick, the ultraviolet blocking function is improved.

< 1-5. Mark >

Marks indicating a manufacturer, a production number, a product name, specifications, and the like may be applied to the surface of the glass sheet of the present invention. The mark may be formed by various methods, and for example, the mark may be formed by a rough surface portion formed on the surface of a glass plate or the surface of an ultraviolet blocking film. That is, the rough surface portion having a predetermined shape is formed by increasing the surface roughness of a part of the surface of the glass plate or the ultraviolet blocking film by shot blasting, wet etching, or the like. The surface roughness Ra of such a rough surface portion may be 1.5 μm or more, for example. Wherein the surface roughness Ra is a surface roughness measured in accordance with JIS B0601: 2001, calculated arithmetic mean roughness.

Or the indicia may be formed from a thin film of opaque material. As the opaque material, a colored ceramic pigment, a conductive paste, and various commercially available products suitable for printing on glass can be used, and they can be printed in a film form on the surface of a glass plate by screen printing or the like to form a mark having a predetermined shape.

< 1-6. Shape of end face of glass plate >

The shape of the end face of the glass plate is not particularly limited, and may be, for example, an arc-shaped curved face 13 having a cross section that is convex outward as shown in fig. 3. Such an end face shape is suitable for a single plate.

Alternatively, as shown in fig. 4, the end face may be formed by 3 or more flat surfaces. For example, the end face 13 is formed by a first side face 111 connected to the first main face 11, a second side face 121 connected to the second main face 12, and a main end face 131 connecting the first side face 111 and the second side face 121. In this case, the angles α and β between the adjacent first side surface 111 and the adjacent main end surface 131 and between the adjacent main end surface 131 and the adjacent second side surface 121 are preferably obtuse angles. The shape of such end faces is suitable for a glass plate used for laminated glass.

< 1-7. Interlayer film of laminated glass >

As shown in fig. 5, the laminated glass has an interlayer film 103 made of resin disposed between an outer glass plate 101 and an inner glass plate 102. The material of the interlayer film 103 is a thermoplastic resin, and a polyvinyl acetal-based or ethylene-vinyl acetate copolymer-based thermoplastic resin can be suitably used from the viewpoint of the adhesion degree to a glass plate when a laminated glass is produced. Among them, polyvinyl butyral (PVB) based thermoplastic resins are preferred. The intermediate film 103 is obtained, for example, by kneading and molding a thermoplastic resin composition containing the above thermoplastic resin and a known plasticizer. In addition, a commercially available thermoplastic resin film may be used as the intermediate film 103.

Examples of the plasticizer that can be used in general intermediate film applications include triethylene glycol di-2-ethylbutyrate (3 GH), triethylene glycol di-2-ethylhexanoate (3 GO), and triethylene glycol di-2-decanoate. These can be used alone, or more than 2 kinds can be used in combination.

The thickness of the intermediate film 103 is not particularly limited, but is preferably 0.3 to 6.0mm, more preferably 0.5 to 4.0mm, and particularly preferably 0.6 to 2.0mm.

The interlayer film 103 may be formed of a plurality of layers. For example, as shown in fig. 6, the intermediate film 103 may be formed of 3 layers by sandwiching a soft core layer 1031 with an outer layer 1032 harder than the soft core layer. However, the present invention is not limited to this configuration, and may be formed of a plurality of layers having a soft core layer 1031. For example, the core layer may be formed of 2 layers including the core layer 1031 (1 layer for core layer and 1 layer for outer layer), an odd number of 5 or more layers including the core layer 1031 at the center (1 layer for core layer and 4 layers for outer layer), or an even number of layers including the core layer 1031 at the inner side (1 layer for core layer and 1 layer for outer layer for other layers). Alternatively, the intermediate film 103 may be formed of one layer.

The core layer 1031 is softer than the outer layer 1032, and in this regard, a material may be selected based on the young's modulus. Specifically, the frequency is preferably 1 to 20MPa, more preferably 1 to 16MPa at 100Hz and a temperature of 20 ℃. More preferably 1 to 10MPa. As a measurement method, for example, DMA50, a solid viscoelasticity measurement apparatus manufactured by Metravib, and frequency dispersion measurement at a strain amount of 0.05% can be used. Hereinafter, in the present specification, unless otherwise specified, the young's modulus is a measured value obtained by the above method. The measured value is used for the measurement at a frequency of 200Hz or less, but the calculated value based on the measured value is used for the measurement at a frequency of more than 200 Hz. The calculated value is a value based on a master curve (master curve) calculated by the WLF method from the measured value.

On the other hand, the young's modulus of the outer layer 1032 is not particularly limited as long as it is larger than the core layer 1031. For example, 560MPa or more, 650MPa or more, 1300MPa or more, and 1764MPa or more are preferable in the order of the frequency of 100Hz and the temperature of 20 ℃. On the other hand, the upper limit of the young's modulus of the outer layer 1032 is not particularly limited, and may be set, for example, from the viewpoint of processability. It is empirically known that, for example, when the pressure is 1750MPa or more, workability, particularly cutting, becomes difficult. In the case where the pair of outer layers 1032 are provided so as to sandwich the core layer 1031, the young's modulus of the outer layer 1032 on the outer glass plate 11 side is preferably made larger than the young's modulus of the outer layer 1032 on the inner glass plate 102 side. This improves the breakage resistance against external force from outside the vehicle or outdoors.

The material constituting each

layer

1031, 1032 is not particularly limited, but at least needs to be a material capable of setting the young's modulus within the above range. For example, outer layer 1032 may be composed of polyvinyl butyral resin (PVB). The polyvinyl butyral resin is preferable because it is excellent in adhesion to each glass plate and penetration resistance. On the other hand, the core layer 1031 may be made of ethylene vinyl acetate resin (EVA) or polyvinyl acetal resin softer than the polyvinyl butyral resin constituting the outer layer 1032. By sandwiching the soft core layer 1031, the sound insulation performance can be greatly improved while securing adhesion and penetration resistance equivalent to those of the single-layer resin interlayer 103.

In general, the hardness of the polyvinyl acetal resin can be controlled by (a) the polymerization degree of polyvinyl alcohol as a starting material, (b) the acetalization degree, (c) the kind of the plasticizer, (d) the addition ratio of the plasticizer, and the like. Therefore, by appropriately adjusting at least 1 condition selected from these, even if the polyvinyl butyral resin is used as well, it is possible to distinguish between the hard polyvinyl butyral resin used for the outer layer 1032 and the soft polyvinyl butyral resin used for the core layer 1031. Further, the hardness of the polyvinyl acetal resin can also be controlled by the kind of aldehyde used for the acetalization, whether it is a co-acetalization using a plurality of aldehydes or a pure acetalization using one aldehyde. Although not possible, there is a tendency that a polyvinyl acetal resin obtained by using an aldehyde having a larger carbon number is softer. Therefore, for example, when the outer layer 1032 is made of a polyvinyl butyral resin, a polyvinyl acetal resin obtained by acetalizing an aldehyde having 5 or more carbon atoms (for example, n-hexanal, 2-ethylbutyraldehyde, n-heptaldehyde, and n-octanal) with polyvinyl alcohol can be used for the core layer. The material for obtaining the predetermined young's modulus is not limited to the above-mentioned resin.

The total thickness of the interlayer film 103 is the same as the above-described film thickness. The thickness of the core layer 1031 is preferably 0.1 to 2.0mm, and more preferably 0.1 to 0.6mm. This is because when the thickness is less than 0.1mm, the effect of the soft core layer 1031 is hardly exerted, and when the thickness is more than 2.0mm or 0.6mm, the total thickness increases, which increases the cost. On the other hand, the thickness of the outer layer 1032 is not particularly limited, but is preferably 0.1 to 2.0mm, and more preferably 0.1 to 1.0mm, for example. In addition, the thickness of the core layer 1031 may be adjusted by making the total thickness of the intermediate film 103 constant.

The thickness of the core layer 1031 can be measured, for example, as follows. First, the cross section of the laminated glass is magnified 175 times by a microscope (for example, VH-5500 manufactured by KEYENCE CORPORATION). Then, the thickness of the core layer 1031 is determined visually. In this case, in order to eliminate the variation due to the visual observation, the number of measurements was 5 times, and the average value thereof was defined as the thickness of the core 1031. For example, a magnified photograph of the laminated glass may be taken, the core layer 1031 therein determined and the thickness thereof measured.

The thickness of the interlayer film 103 is not necessarily constant over the entire surface, and may be formed in a wedge shape for a laminated glass used for a head-up display, for example. At this time, the thickness of the interlayer film 103 was measured at the lowest thickness portion, i.e., the lowermost edge portion of the laminated glass.

The method for producing the intermediate film 103 shown in fig. 6 is not particularly limited, and examples thereof include: a method in which the resin component such as the polyvinyl acetal resin, the plasticizer, and other additives as needed are mixed and kneaded uniformly, and then the layers are extruded together; a method of laminating 2 or more resin films produced by this method by a pressure method, a lamination method, or the like. The resin film before lamination used in a method of laminating by a pressure method, a lamination method, or the like may have a single-layer structure or a multi-layer structure.

< 2. Ultraviolet ray blocking film >

The ultraviolet blocking film is a film containing a component (ultraviolet absorber) that absorbs ultraviolet rays. The ultraviolet absorber may be present in a state dissolved in a matrix component constituting the film, or may be present in a state dispersed in the matrix component in the form of fine particles. The matrix component may be any component that can maintain the ultraviolet absorber while ensuring transparency as a film. Therefore, for example, inorganic components such as silica, alumina, and titanium may be used as the main component, or organic components such as polyester resins, urethane acrylate resins, epoxy resins, and polyvinyl acetal resins may be used as the main component. The method for producing the film is not particularly limited, and the ultraviolet ray blocking film can be formed by applying a film-forming solution containing an ultraviolet ray absorber and a matrix component on a glass body and drying the film or by heating and drying the film as necessary. The details will be described below.

First, 3 kinds of components constituting a film forming solution for forming an ultraviolet ray blocking film will be described, and thereafter, a method for preparing the film forming solution will be described below.

< 2-1. Film-forming solution 1 >

(silicon Compound A)

The silicon compound A is a compound represented by the formula (3).

SiX ¹ ₄ (3)

In formula (3), X ¹ Is a hydrolyzable functional group or a halogen atom. The hydrolyzable functional group is a functional group that is hydrolyzed by the hydrolysis catalyst, and is, for example, at least 1 selected from the group consisting of an alkoxy group, an acyloxy group, and an alkenyloxy group. All of the hydrolyzable functional groups exemplified above are converted to hydroxyl groups by hydrolysis. Preferred hydrolyzable functional groupsIs an alkoxy group. Examples of the alkoxy group include alkoxy groups having 1 to 4 carbon atoms (methoxy, ethoxy, propoxy and butoxy groups). Halogen atoms are, for example, chlorine and bromine, preferably chlorine.

Examples of the preferable silicon compound a include tetraalkoxysilane, and specifically tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane. Instead of or in addition to the silicon compound a, a compound obtained by at least partially hydrolyzing the silicon compound a in advance, or a compound obtained by at least partially hydrolyzing the silicon compound and then polycondensing the hydrolyzed compound may be used. The hydrolysate of silicon compound a and the like can be purchased as a commercially available product.

(silicon Compound B)

The silicon compound B is a compound represented by the formula (4).

R ¹ _m R ² _n SiX ² _4-m-n (4)

In the formula (4), R ¹ Is an organic radical having a reactive functional group, R ² Is an organic radical having no reactive functional groups, X ² Is a hydrolyzable functional group or a halogen atom, m is an integer of 0 to 2, n is an integer of 0 to 2, and m + n is 1 to 2.

The reactive functional group is, for example, at least 1 selected from the group consisting of a vinyl group, an acryloyl group, a methacryloyl group, an isocyanurate group, a ureido group, a mercapto group, a thioether group, an isocyanate group, an epoxy group and an amino group. The epoxy group may be part of a glycidyl group, particularly an oxyglycidyl group. The amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group. Preferred reactive functional groups are epoxy and amino groups, in particular epoxy groups. The organic group having a reactive functional group may be, for example, an aliphatic hydrocarbon group or an aromatic hydrocarbon group in which the organic group itself is a reactive functional group (for example, a vinyl group), or at least 1 hydrogen atom is substituted with a reactive functional group. Examples of the aliphatic hydrocarbon group include a straight-chain alkyl group having 1 to 10 carbon atoms and a branched-chain alkyl group having 3 to 10 carbon atoms. As the aromatic hydrocarbon group, a phenyl group can be exemplified.

The organic group having no reactive functional group is, for example, an aliphatic or aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include a straight-chain alkyl group having 1 to 10 carbon atoms and a branched-chain alkyl group having 3 to 10 carbon atoms. As the aromatic hydrocarbon group, a phenyl group can be exemplified.

X ² Is a hydrolyzable functional group or a halogen atom, X ² Specific examples of (2) and X ¹ The same applies to specific examples.

m may be 1 or 2, preferably n is 0 or 1, m + n may be 1 or 2.

The silicon compound B may contain a silicon compound B1 in which m is 1 or 2 and n is 0 or 1 in the formula (4). Examples of the silicon compound B1 include vinyltriethoxysilane, p-vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, tris- (trimethoxysilylpropyl) isocyanurate, 3-ureidopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane. The silicon compound B1 is a so-called silane coupling agent. In the silicon compound B1, as R ¹ The reactive functional group contained preferably has an epoxy group.

The silicon compound B may contain an organic group R having a reactive functional group in which m in the formula (4) is 0 (no organic group having a reactive functional group ¹ ) And n is 1 or 2. The preferable silicon compound B2 is a silane oxygen compound having a phenyl group, and specifically, phenyltriethoxysilane is exemplified.

(ultraviolet absorber)

Examples of the ultraviolet absorber include benzotriazole compounds [ e.g., 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole and 2- (2 '-hydroxy-3', 5 '-di-t-butylphenyl) benzotriazole ], benzophenone compounds [ e.g., 2',4 '-tetrahydroxybenzophenone, 2, 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 5' -methylenebis (2-hydroxy-4-methoxybenzophenone) ], hydroxyphenyltriazine compounds [ e.g., 2- (2-hydroxy-4-octyloxyphenyl) -4, 6-bis (2, 4-di-t-butylphenyl) s-triazine, 2- (2-hydroxy-4-methoxyphenyl) -4, 6-diphenyls-triazine, 2- (2-hydroxy-4-propoxy-5-methylphenyl) -4, 6-bis (2, 4-di-t-butylphenyl) s-triazine ] and cyanoacrylate compounds [ e.g., ethyl- α -cyano- β, β -diphenylacrylate and methyl-2- (3-cyano-3-methoxyphenyl) acrylate ]. The ultraviolet absorber may be at least 1 organic dye selected from the group consisting of polymethine compounds, imidazoline compounds, coumarin compounds, naphthalimide compounds, perylene compounds, azo compounds, isoindolinone compounds, quinophthalone compounds and quinoline compounds, thiophene compounds, stilbene compounds, naphthalene compounds, and benzimidazole compounds. Among the ultraviolet absorbers, at least 1 selected from the group consisting of benzotriazole compounds, benzophenone compounds, hydroxyphenyltriazine compounds, and cyanoacrylate compounds is preferable, and benzophenone compounds are more preferable. The ultraviolet absorber may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The ultraviolet absorber preferably has at least 1 selected from amino groups and hydroxyl groups, particularly hydroxyl groups, in a molecule, and particularly preferably has 2 or more hydroxyl groups in 1 molecule. Here, the amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group. The ultraviolet absorber may have a benzene skeleton to which 2 or more hydroxyl groups are bonded.

The ultraviolet absorber can be used as it is without having to be reacted with a silicon compound such as the silicon compound B1 in advance to conduct silylation. Therefore, in the present embodiment, the ultraviolet absorber containing no silicon atom in the molecule can be used as it is for the preparation of the film forming solution. The silylation of the ultraviolet absorber is effective for suppressing the bleeding of the ultraviolet absorber, but a preliminary step is required only for this purpose. In the present embodiment, the ultraviolet absorber is generally reacted or intermolecular-interacted with other components capable of reacting or intermolecular-interacting with the ultraviolet absorber, specifically, the silicon compound a, the silicon compound B, the organic polymer, and the like in the film-forming solution. The reaction or intermolecular interaction occurs competitively. Here, as an example of the reaction, a reaction of forming a covalent bond or an ionic bond can be cited. As examples of intermolecular interactions, hydrogen bonds or π - π interactions may be cited. Therefore, even if the film-forming solution contains the silicon compound B1 (silane coupling agent), the ultraviolet absorber does not react with the silicon compound B1 in the entire amount or interact with molecules, and usually at least a part thereof reacts with at least 1 selected from the group consisting of the silicon compound a, the silicon compound B (but excluding the silicon compound B1), and the organic polymer or interacts with molecules. This reaction or intermolecular interaction, like the reaction with the silicon compound B1, fixes the ultraviolet absorber in the film, thereby contributing to suppression of bleeding.

(organic Polymer)

As the organic polymer, for example, polyethylene glycol, polyether-based resin, polyurethane resin, starch-based resin, cellulose-based resin, acrylic resin, polyester polyol, hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polycaprolactone polyol, polyvinyl acetal resin, polyvinyl acetate, polyalkylene glycol-based resin, and the like are known. The organic polymer preferred in the present embodiment is an organic polymer having an epoxy group in the molecule. The organic polymer may be present in the film-forming solution or the ultraviolet blocking film in the form of an organic polymer formed by ring-opening of at least a part of epoxy groups, or in some cases all of the epoxy groups. Examples of another preferable organic polymer include organic polymers containing a polar group (carbonyl group, hydroxyl group, phenolic hydroxyl group, or the like) capable of forming a hydrogen bond with a silanol group or a phenolic hydroxyl group. Among them, the organic polymer is particularly preferably a polyalkylene glycol-based resin. Examples of the polyalkylene glycol resin include polyethers and polyether derivatives as glycols, and examples of these polymers include polypropylene glycol and polyethylene glycol dimethacrylate. When the polyalkylene glycol resin is used, the generation of foreign matter in the ultraviolet ray blocking film can be effectively suppressed, and a film having high abrasion resistance can be obtained even when the drying temperature after the film forming solution is applied is low. As still another preferable organic polymer, an organic polymer containing an organic group (e.g., a phenyl group, an alkenyl group having a conjugated double bond, etc.) capable of pi-pi interaction with an aromatic ring of an ultraviolet absorber can be exemplified, and as an example of the polymer, a bisphenol polyol can be exemplified. The organic polymer is preferably an organic polymer soluble in ethanol and/or water. The solubility in ethanol (water) is determined by whether or not the organic polymer dissolves in 100g of ethanol (water) at 25 ℃ by 1g or more. Since the organic polymer does not require ultraviolet absorbing ability, compounds other than ultraviolet absorbers, specifically, compounds other than the above-exemplified compounds from benzotriazole compounds to cyanoacrylate compounds and organic pigments can be used as the organic polymer. The organic polymer having an epoxy group may have an average number of epoxy groups in a molecule of 2 to 10.

Examples of the organic polymer having an epoxy group include polyglycidyl compounds such as polyglycidyl ether compounds, polyglycidyl ester compounds, and polyglycidyl amine compounds. The organic polymer having an epoxy group may be any of an aliphatic polyepoxy compound and an aromatic polyepoxy compound, and is preferably an aliphatic polyepoxy compound. Preferred organic polymers having epoxy groups are polyglycidyl ether compounds, in particular aliphatic polyglycidyl ether compounds. The polyglycidyl ether compound is preferably a glycidyl ether of an alcohol having 2 or more hydroxyl groups. Among them, the alcohol is preferably an aliphatic alcohol, an alicyclic alcohol, or a sugar alcohol.

Examples of the glycidyl ether of an alcohol having 2 or more hydroxyl groups include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, and pentaerythritol polyglycidyl ether. These may be used alone in 1 kind, or 2 or more kinds may be used in combination.

Among these, from the viewpoint of the abrasion resistance of the ultraviolet ray blocking film, a polyglycidyl ether of an aliphatic polyhydric alcohol having 3 or more hydroxyl groups (a substance having an average number of glycidyl groups (epoxy groups) per 1 molecule of more than 2) such as glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, and the like is preferable.

The organic polymer is a component contributing to improvement of dispersibility of the ultraviolet absorber by utilizing high affinity with the ultraviolet absorber which is also an organic substance, and to inhibition of bleeding out, and is a component contributing to improvement of flexibility of the film, to making the film less likely to crack even when the film thickness is thick, and to improvement of abrasion resistance of the film. In addition, the organic polymer having an epoxy group is a component contributing to improvement of adhesion of a film formed on a surface of a transparent substrate (glass body) having low reactivity.

(acid)

The acid has an acid dissociation constant of less than 1 and a boiling point of 130 ℃ or less, and may be an inorganic acid or an organic acid. As the inorganic acid, at least 1 selected from hydrochloric acid, nitric acid, hydrobromic acid, and hydroiodic acid can be cited, and hydrochloric acid and nitric acid are preferable. These volatile acids are easier to remove by heating than nonvolatile inorganic acids typified by sulfuric acid and phosphoric acid.

Examples of the organic acid include trifluoroacetic acid (pKa: 0.23, boiling point: 72.4 ℃ C.). Organic acids having a low boiling point are easily removed by heating, as are volatile inorganic acids. In the present embodiment, an acid which can be easily removed in the drying step can be used as a hydrolysis catalyst regardless of whether it is an inorganic acid or an organic acid. The components derived from the residual hydrolysis catalyst in the film may cause deterioration of the transparency of the film after long-term use.

As is well known, the chemical formula of the acid is denoted as [ HA ]]The pKa of the acid is calculated from the following formula. pKa = -log { [ H ] ₃ O ⁺ ][A ^- ]/[HA]}

Wherein [ H ] ₃ O ⁺ ]Represents the hydrogen ion concentration (mol/L) in the aqueous acid solution, [ A ] ^- ]Represents the alkali concentration (mol/L) in the aqueous acid solution, [ HA ]]Represents the concentration (mol/L) of HA in an aqueous solution. Wherein, in the case where an acid is dissociated from an acidic group of HA in multiple steps, pKa represents the firstAcid dissociation constant of one step.

When an acid having a pKa of less than 1 is used, a denser ultraviolet blocking film is easily obtained as compared with the case where an acid having a relatively high pKa is used as a hydrolysis catalyst. The abrasion resistance of the membrane is improved due to the increased compactness of the membrane.

The boiling point of the acid is preferably 100 ℃ or lower, and may be 80 ℃ or lower.

The acid is preferably at least 1 selected from the group consisting of hydrochloric acid, nitric acid and trifluoroacetic acid.

The film-forming solution may contain an infrared absorber. Examples of the infrared absorber include: organic infrared absorbers such as polymethine compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, dithiol compounds, iminium compounds, diiminium compounds, ammonium compounds, pyrylium compounds, cerium (12475125221251255412512max), squaraine compounds, and combinations of counter ions of dithiolene metal ligand anions and cyanine dye cations; and inorganic infrared absorbers such as tungsten oxide, tin oxide, indium oxide, magnesium oxide, titanium oxide, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, zinc oxide, iron oxide, antimony oxide, lead oxide, bismuth oxide, lanthanum oxide, tungsten oxide, indium tin oxide, antimony tin oxide, fluorine-doped tin oxide, and the like. The infrared absorber may be used alone or in combination of 2 or more. The infrared ray absorber is preferably at least 1 selected from the group consisting of indium tin oxide, antimony tin oxide and fluorine-doped tin oxide.

The film-forming solution may contain inorganic oxide fine particles. The inorganic oxide constituting the inorganic oxide fine particles is, for example, an oxide of at least 1 element selected from Si, ti, zr, ta, nb, nd, la, ce, and Sn, and is preferably silica fine particles. The silica fine particles can be introduced into the film-forming solution by adding colloidal silica, for example. The inorganic oxide fine particles are excellent in the effect of transmitting the stress applied to the ultraviolet ray blocking film to the substrate supporting the ultraviolet ray blocking film, and also have high hardness. Therefore, from the viewpoint of improving the abrasion resistance of the ultraviolet ray blocking film, it is advantageous to add inorganic oxide fine particles.

In the film-forming solution, an organic solvent is preferably added in order to improve the solubility of organic substances in the constituent components. The organic solvent is preferably a solvent mixed with water at an arbitrary ratio, and particularly preferably a lower alcohol having 1 to 3 carbon atoms (methanol, ethanol, propanol).

Other additives may be added to the film-forming solution. As the additive, a surfactant having a function of improving the appearance of the ultraviolet ray blocking film and the dispersibility of the ultraviolet ray absorber can be cited. As the additive, a leveling agent, an antifoaming agent, a preservative, and the like may be added.

CA, which is a component produced by condensation polymerization of a hydrolysate of a silicon compound A represented by the formula (3), is SiO ₂ . The component CB formed by condensation polymerization of the hydrolyzate of the silicon compound B represented by the formula (4) may be represented by [ R ] ¹ _m R ² _n SiO _(4-m-n)/2 ]And (4) showing. The component CB includes a component CB1 formed by polycondensation of a hydrolysate of the silicon compound B1 and a component CB2 formed by polycondensation of a hydrolysate of the silicon compound B2. Wherein R is ¹ 、R ² M and n are as described above.

The ratio (p/r) of the total mass p of the component CA to the total mass r of the component CA and the component CB is preferably 0.1 or more and less than 0.8, more preferably 0.35 or more and 0.48 or less, and may be 0.40 or more and 0.48 or less. The ratio (q/r) of the total mass q of the component CB to the total mass r of the component CA and the component CB is preferably more than 0.2 and 0.9 or less, more preferably 0.52 to 0.65, and may be 0.52 to 0.60. The ratio (c/r) of the mass c of the component CB1 to the total mass r of the component CA and the component CB may be 0 to 0.9. The ratio (d/r) of the mass d of the component CB2 to the total mass r of the component CA and the component CB may be 0 to 0.4.

The ratio (s/r) of the mass s of the organic polymer to the total mass r of the component CA and the component CB is preferably 0.001 to 1, more preferably 0.001 to 0.8, and may be 0.001 to 0.6.

The film-forming solution is preferably prepared so that the above-mentioned ratios (p/r), (q/r), (c/r), (d/r) and (s/r) are all within desired ranges. The ultraviolet absorber is preferably contained in the film-forming solution in an amount such that the content of the ultraviolet absorber in the formed ultraviolet barrier film is 0.5 to 40% by mass, and more preferably 10 to 40% by mass. The ratio (e/r) of the mass e of the ultraviolet absorber to the total mass r of the component CA and the component CB may be 0.005 to 0.7.

The content of the acid in the film-forming solution is preferably 0.001 to 1% by mass, more preferably 0.001 to 0.6% by mass, based on the mass of the film-forming solution.

The number of moles of water in the film-forming solution is preferably 15 times or less, more preferably 4 to 12 times, for example, 4 to 10 times, relative to the total number of moles of silicon atoms contained in the film-forming solution. When the number of moles of water is controlled to be not too large, a transparent film can be easily obtained. Further, when the number of moles of water is not too small and at least the above-described level is secured, a more dense film having high abrasion resistance can be easily obtained.

The method for preparing the film-forming solution is not particularly limited, and the above-described respective components may be supplied to 1 container, for example, a mixing tank with a stirring device, in order without any particular restriction, and stirred. In the vessel, only an ultraviolet absorber which does not react with either of the silicon compound A and the silicon compound B is supplied as the ultraviolet absorber. In other words, the entire amount of the ultraviolet absorber is supplied into the container without undergoing the silylation treatment using the silicon compound a and the silicon compound B. In the present embodiment, it is preferable that only an acid having an acid dissociation constant of less than 1 and a boiling point of 130 ℃ or lower is supplied as the hydrolysis catalyst in the vessel.

< 2-2. Film-forming solution 2 >

A preferable embodiment of the film forming solution by the sol-gel method will be described.

The organic solvent used in the sol-gel method must have high compatibility with silicon alkoxide and water and be a solvent capable of allowing the sol-gel reaction to proceed, and is preferably a lower alcohol having 1 to 3 carbon atoms. The silicon alkoxide is not particularly limited, and silicon tetramethoxyxide, silicon Tetraethoxide (TEOS), silicon tetraisopropoxide, or the like can be used. A hydrolysate of silicon alkoxide may also be used as the silicon raw material. In forming solutions by sol-gel processConcentration of silicon alkoxide to convert silicon alkoxide to SiO ₂ SiO of (2) ₂ The concentration is preferably 3 to 15% by mass, and particularly preferably 3 to 13% by mass. If the concentration is too high, the film may crack.

The molar ratio of water to the silicon alkoxide is preferably 4 times or more, specifically 4 to 40 times, and preferably 4 to 35 times. As the hydrolysis catalyst, an acid catalyst is preferably used, and particularly strong acids such as hydrochloric acid, nitric acid, sulfuric acid, trichloroacetic acid, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid and the like are preferably used. Since organic materials derived from an acid catalyst may lower the film hardness, it is preferable to use an inorganic acid as the acid catalyst. Hydrochloric acid is highly volatile and does not easily remain in the film, and is therefore the most preferred acid catalyst. The concentration of the acid catalyst is preferably in the range of 0.001 to 2mol/kg in terms of the molar mass concentration of protons when protons are completely dissociated from the acid.

When water is added in an excessive amount to the above-mentioned extent and the acid catalyst is added in a concentration to the above-mentioned extent, for example, as described in international publication No. 2005/095101, a relatively thick film can be easily formed by the sol-gel method in a temperature range in which decomposition of organic substances can be prevented.

The ultraviolet blocking film forming solution can be prepared by mixing the film forming solution by the sol-gel method containing the above-listed components with a dispersion liquid in which ultraviolet absorber fine particles are dispersed, and adding an organic polymer or the like as necessary. However, the method for preparing the ultraviolet-ray-blocking film-forming solution is not limited to this, and components necessary for forming a film by a sol-gel method may be added to the fine particle dispersion in order, and as a method for forming a film by a method other than the sol-gel method, a forming solution containing ultraviolet-ray-absorbing agent fine particles and components necessary for the method (for example, polysilazane) may be prepared.

(ultraviolet absorber)

The ultraviolet absorber is not particularly limited as long as it is a solid at room temperature, has a molecular weight of 5000 or less, and can be pulverized into an average particle size of 150nm or less, and conventionally known ultraviolet absorbers such as benzotriazole-based, benzophenone-based, triazine-based, polymethine-based, imidazoline-based, and the like can be used. Further, as long as it has an ultraviolet-blocking function, an organic compound conventionally used for other applications, such as a thiophenol copper complex derivative described later, may be used.

The molecular weight of the ultraviolet absorber is preferably 3000 or less, more preferably 2000 or less, further preferably 1500 or less, and in some cases may be 1300 or less, and may be 1200 or less, particularly 900 or less, and particularly 800 or less. However, when the molecular weight of the ultraviolet absorber is too low, it is difficult to maintain the solid at room temperature. Therefore, the molecular weight of the ultraviolet absorber is preferably 200 or more, more preferably 300 or more, and still more preferably 500 or more.

The ultraviolet absorber preferably does not contain a polymerizable carbon-carbon double bond in the molecule. Examples of the polymerizable carbon-carbon double bond include double bonds contained in polymerizable functional groups such as vinyl groups, vinylene groups, and vinylidene groups. The ultraviolet absorber preferably does not contain these functional groups in the molecule.

A preferred example of the ultraviolet absorber is an organic compound α having 2 or more, for example, 2 to 8, preferably 2 to 4 functional groups represented by the following formula (5) in the molecule.

Here, A ₁ ～A ₅ Each independently a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 5 to 15 carbon atoms, more preferably 7 to 13 carbon atoms, or a functional group represented by the following formula (6). Wherein A is ₁ ～A ₅ At least 1 of (3) is a functional group represented by the following formula (6).

The organic compound α is a benzotriazole-based ultraviolet absorber having at least 2 benzotriazole structures (see formula (6)) in the molecule. The presence of at least 2 benzotriazole structures in 1 molecule contributes to the ultraviolet blocking effect of the organic compound α, and also contributes to ensuring a large molecular weight to the extent that the organic compound α is in a solid state at room temperature. It is well known that the melting point of a compound is not determined only by the molecular weight, but the molecular weight is a factor that largely influences the melting point. The organic compound α is a compound suitable for forming an ultraviolet ray blocking film having excellent durability of the ultraviolet ray blocking effect and low haze, which is a property particularly important in the case of a glass laminate.

Among the functional groups represented by the formula (5), for example, A may be mentioned ₁ ～A ₅ Wherein 1 is a hydroxyl group, 1 is an alkyl group defined above, 1 is a functional group represented by formula (6), and the remaining 2 are hydrogen atoms. Specifically, the organic compound α preferably has 2 or more functional groups represented by the following formula (7) in the molecule. In the formula (7), R ₁ Is a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 5 to 15 carbon atoms, more preferably 7 to 13 carbon atoms.

Further, since the organic compound α tends to have higher hydrophobicity as a whole molecule as the number of carbon atoms of the alkyl group contained therein increases, it is likely to exist in the form of fine particles in a film made of a dispersion liquid in which the dispersion medium is water. However, when the number of carbon atoms is too large, the melting point of the organic compound α tends to decrease due to the influence of steric hindrance or the like.

In a preferred embodiment of the present invention, the organic compound α has a structural unit in which 2 functional groups represented by formula (7) are linked through an alkylene group. The number of carbon atoms constituting the alkylene group is preferably 3 or less, and particularly preferably 2 or less.

The organic compound α may be a compound represented by the following formula (8).

Herein, R is ₁ And R ₂ Independently of each other, a straight-chain or branched alkyl group having 1 to 20 carbon atoms, preferably 5 to 15 carbon atoms, more preferably 7 to 13 carbon atoms.

Another preferable example of the ultraviolet absorber is an organic compound β having a structural unit represented by the following formula (8) in a molecule. The organic compound beta is a thiophenol copper complex derivative.

The copper benzenedithiol complex participates in absorption of light having a wavelength of about 400nm due to a resonance effect derived from the structure represented by formula (9). The wavelength absorbed by the resonance effect is shifted when Cu is replaced with another metal atom (for example, when Cu is replaced with Zn or Al, the resonance effect is obtained in a shorter wavelength region). When importance is attached to the absorption performance of light having a wavelength of about 400nm, cu is most preferable as the metal atom.

Due to the increasing demand for ultraviolet blocking properties of glass plates, it is desirable to shield the glass plates not only to the extent of shielding but also to the longer wavelength side than the ultraviolet region. In recent years, shielding is required not only for light having a wavelength in the ultraviolet region but also in the short wavelength region (wavelength region of about 400 nm) in the visible region. The use of the organic compound β having a structure represented by formula (9) is effective not only in shielding ultraviolet region but also in shielding light in a wavelength region of about 400 nm.

The organic compound β preferably has a structure represented by the following formula (10), more preferably has a structure represented by the following formula (11), and may be a compound of the formula (15), for example.

Here, L and M are each independently a group represented by any one of the following formulae (12), (13), and (14). Further, a is a quaternary ammonium salt. Examples of the quaternary ammonium salt include tetramethylammonium salt, tetraethylammonium salt, tetraisopropylammonium salt, tetrabutylammonium salt, tetraphenylammonium salt, tetrabenzylammonium salt, and trimethylbenzylammonium salt.

Herein, R is ₃ 、R ₄ Each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms.

Here, n is an integer of 3 to 5.

Here, bu is a straight-chain or branched butyl group.

The ultraviolet absorber is solid at normal temperature. In the present specification, "normal temperature" is used as a term indicating 25 ℃. As described above, in the related art, the ultraviolet ray blocking film formed of a solution uses an ultraviolet ray absorber which is liquid at normal temperature. In the ultraviolet ray blocking film formed using a solution obtained by emulsifying such an ultraviolet ray absorber, the ultraviolet ray absorber is dispersed in the form of a fine liquid. In addition, in the prior art, in order to uniformly distribute in the film, an organic compound which is solid at ordinary temperature is generally introduced into the film after being dissolved in a solvent. This is because the organic compound introduced in a solid state into the film formed on the glass plate often impairs the transparency of the glass laminate. In contrast, in the present invention, the ultraviolet absorber is dispersed in the ultraviolet blocking film in the form of fine particles having an average particle diameter of 150nm or less. By finely pulverizing the ultraviolet absorber to an average particle diameter of 150nm or less and introducing the same into the film, the film is excellent in the persistence of ultraviolet blocking performance and does not impair transparency. The ultraviolet absorber introduced into the film in this manner is preferably kept in a crystalline state also in the film. The maintenance of the crystalline state of the ultraviolet absorber in the film can be confirmed by X-ray diffraction.

The time for the ultraviolet absorber to be pulverized to have a predetermined average particle diameter depends on pulverization conditions such as the type, the amount of the pulverization apparatus to be charged, and the number of revolutions. Therefore, in mass production, the time until the predetermined average particle size is obtained can be determined in advance while repeating the operation of appropriately interrupting the pulverization by the pulverization device and checking the average particle size of the pulverized material sampled. In addition, a surfactant, a water-soluble resin, or the like may be added to the ultraviolet absorber to be pulverized as appropriate.

The ultraviolet absorber may be dispersed in the film in the form of fine particles having an average particle diameter of 150nm or less, preferably 10 to 150nm, more preferably 50 to 140nm, and particularly preferably 70 to 140nm. In the case of preparing a fine particle dispersion (fine particle dispersion composition), it is also preferable to pulverize the ultraviolet absorber in advance so as to have an average particle diameter in this range. When the average particle diameter of the fine particles is too large, the transparency of the film is lowered; when it is too small, deterioration of ultraviolet absorption performance or reduction in durability may be caused. The "average particle size" is a value based on a measurement value obtained by a dynamic light scattering method, which is one of photon correlation spectroscopy, including a measurement value in the column of examples described later, and specifically, is a particle size in which a cumulative frequency in a volume-based distribution of spherical equivalent diameters reaches 50%. The "average particle diameter" can be measured, for example, by using "Microtrac ultrafine particle size distribution meter 9340-UPA150" manufactured by Nikkiso K.K.

Relative to silicon oxide (SiO) in the film ₂ In terms of mass%), preferably 1 to 80%, more preferably 5 to 60%, particularly preferably 5 to 50%, and particularly preferably 7 to 30%. In consideration of this, the amount of the ultraviolet absorber added is also% by mass based on the liquid amount of the film-forming solutionThis expression is preferably 0.5 to 25%, more preferably 0.5 to 15%.

(organic Polymer)

The organic polymer is a component which contributes to improvement of dispersibility of the ultraviolet absorber in the film, improvement of light-shielding ability by the compound, and suppression of deterioration of the compound by interacting with the ultraviolet absorber (benzotriazole-based ultraviolet absorber). When a relatively thick ultraviolet blocking film (e.g., a thickness of more than 300nm, and further a thickness of 500nm or more) is formed by liquid-phase film formation such as a sol-gel method, cracks may occur as liquid components contained in the film-forming solution evaporate. The organic polymer is also a component capable of suppressing the generation of cracks and forming a thick film.

The organic polymer is preferably at least 1 selected from the group consisting of polyether compounds, polyol compounds, polyvinyl pyrrolidones, and polyvinyl caprolactams. The organic polymer may be a polyether compound such as a polyether surfactant, or a polyol compound such as polycaprolactone polyol or bisphenol a polyol. The organic polymer may also be polyethylene glycol, polypropylene glycol, and the like. The polyether compound means a compound containing 2 or more ether bonds, and the polyol compound means a polyol including a diol and a triol. The polyvinyl pyrrolidone is polyvinyl pyrrolidone and its derivatives, and the polyvinyl caprolactam is polyvinyl caprolactam and its derivatives.

Relative to silicon oxide (SiO) in the film ₂ In terms of mass%), preferably 0 to 75%, more preferably 0.05 to 50%, particularly preferably 0.1 to 40%, particularly preferably 1 to 30%, in some cases preferably 10% or less, and if necessary preferably 7% or less. In the case where the amount of the ultraviolet absorber is large, the organic polymer can be reduced by the amount.

The type of silane coupling agent is not particularly limited, and RSiX is preferred ₃ (R is an organic functional group containing at least 1 selected from the group consisting of a vinyl group, a glycidoxy group, a methacryloxy group, an amino group and a mercapto group, and X is a halogen or an alkoxy group). The R group of the silane coupling agent reacts with the organic matter,the X group reacts with inorganic substances. By this reaction, the silane coupling agent can exert effects of contributing to improvement of dispersibility of the ultraviolet absorber in the film, suppression of generation of cracks, and formation of a thick film. Relative to silicon oxide (SiO) in the film ₂ Converted), the amount of the silane coupling agent added to the film is preferably 0 to 40%, more preferably 0.1 to 20%, and further preferably 1 to 10% in terms of mol%.

The ultraviolet blocking film of the present invention may contain functional components other than the ultraviolet absorber, the organic polymer and the silane coupling agent. For example, indium Tin Oxide (ITO) fine particles known as a near-infrared absorber are one of preferable components to be added to the ultraviolet blocking film.

The ITO fine particles may be dispersed in the film in the form of fine particles having an average particle diameter of 200nm or less, preferably 5 to 150 nm. When the particle diameter is too large, the transparency of the film is lowered, as in the case of the ultraviolet absorber fine particles; when it is too small, the addition effect cannot be sufficiently obtained. The ITO fine particles may be added to the film-forming solution after preparing a dispersion in advance.

The ultraviolet ray blocking film contains silicon oxide as an inorganic component. The ultraviolet ray blocking film may contain an inorganic component other than silicon oxide. Examples of the inorganic component other than silica include, in addition to the ITO fine particles, components derived from an acid catalyst used in a sol-gel method (for example, chlorine, nitrogen, and sulfur atoms). The silicon oxide contained in the ultraviolet ray blocking film is added to the film forming solution in the form of a silicon-containing compound (silicon compound) such as silicon alkoxide.

The silicon oxide in the ultraviolet ray blocking film may account for 30 mass% or more, preferably 40 mass% or more, more preferably 50 mass% or more (in this case, silicon oxide becomes a main component of the film), and sometimes 70 mass% or more of the entire film. The ultraviolet blocking film preferably has a form in which silicon oxide is the main component, and fine particles of an ultraviolet absorber and other components are dispersed in a network of Si — O bonds. The film having such a form is suitable for outdoor use such as window glass.

< 2-3. Film-forming solution 3 >

The film-forming solution contains an organic substance and an inorganic oxide. The organic material contains a water-absorbent resin, and the inorganic oxide contains silica. The film-forming solution contains an ultraviolet absorber and/or an infrared absorber. The respective components are explained below.

(Water-absorbent resin)

The water-absorbent resin is not particularly limited, and examples thereof include polyethylene glycol, polyether resins, polyurethane resins, starch resins, cellulose resins, acrylic resins, epoxy resins, polyester polyols, hydroxyalkyl celluloses, polyvinyl alcohols, polyvinyl pyrrolidones, polyvinyl acetal resins, and polyvinyl acetates. Among these, preferred are hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal resin, polyvinyl acetate, epoxy resin, and polyurethane resin, more preferred are polyvinyl acetal resin, epoxy resin, and polyurethane resin, and particularly preferred is polyvinyl acetal resin.

The polyvinyl acetal resin can be obtained by acetalizing an aldehyde by condensation reaction with polyvinyl alcohol. The acetalization of polyvinyl alcohol can be carried out by a known method such as a precipitation method using an aqueous medium in the presence of an acid catalyst, or a dissolution method using a solvent such as alcohol. Acetalization can also be carried out in parallel with the ketonization of the polyvinyl acetate. The acetalization degree is preferably 2 to 40 mol%, more preferably 3 to 30 mol%, particularly preferably 5 to 20 mol%, and may be preferably 5 to 15 mol%. The degree of acetalization can be based, for example, on ¹³ C nuclear magnetic resonance spectrometry. The polyvinyl acetal resin having the acetalization degree within the above range is suitable for forming a film-forming solution excellent in water absorption and water resistance.

The average polymerization degree of the polyvinyl alcohol is preferably 200 to 4500, more preferably 500 to 4500. A high average polymerization degree is advantageous for forming a film-forming solution having good water absorption and water resistance, but when the average polymerization degree is too high, the viscosity of the solution becomes too high, which may hinder film formation. The degree of ketonization of the polyvinyl alcohol is preferably 75 to 99.8 mol%.

Examples of the aldehyde that is condensation-reacted with the polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butylaldehyde, hexyl formaldehyde (hexyl carbamate), octyl formaldehyde (octyl carbamate), and decyl formaldehyde (decyl carbamate). Mention may also be made of: benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl-substituted benzaldehydes; chlorobenzaldehyde, other halogen atom-substituted benzaldehydes; substituted benzaldehydes in which the hydrogen atom is substituted with a functional group other than an alkyl group, such as a hydroxyl group, an alkoxy group, an amino group, or a cyano group; aromatic aldehydes such as fused aromatic cyclic aldehydes including naphthaldehyde and anthracenal. Aromatic aldehydes having strong hydrophobicity are advantageous in forming a film-forming solution having a low degree of acetalization and excellent water resistance. The use of an aromatic aldehyde is advantageous in forming a film which retains a large amount of hydroxyl groups and has high water absorption. The polyvinyl acetal resin preferably contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

Examples of the epoxy resin include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and cyclic aliphatic epoxy resins. Among these, cyclic aliphatic epoxy resins are preferable.

The polyurethane resin includes a polyurethane resin composed of a polyisocyanate and a polyol. The polyol is preferably an acrylic polyol or polyoxyalkylene polyol.

The film-forming solution contains a water-absorbent resin as a main component. In the present invention, "main component" means a component having the highest content on a mass basis. From the viewpoint of film hardness, water absorption, and antifogging property, the content of the water-absorbent resin is preferably 50% by weight or more, more preferably 60% by weight or more, particularly preferably 65% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less, particularly preferably 85% by weight or less, based on the weight of the film-forming solution.

(inorganic oxide)

The inorganic oxide is, for example, an oxide of at least 1 element selected from Si, ti, zr, ta, nb, nd, la, ce, and Sn, and an oxide (silica) containing at least Si. The inorganic oxide is preferably contained in the film-forming solution in an amount of 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, further preferably 0.2 parts by weight or more, particularly preferably 1 part by weight or more, most preferably 5 parts by weight or more, and in some cases 10 parts by weight or more, and if necessary 20 parts by weight or more, and preferably 50 parts by weight or less, more preferably 45 parts by weight or less, further preferably 40 parts by weight or less, particularly preferably 35 parts by weight or less, most preferably 33 parts by weight or less, and in some cases 30 parts by weight or less, based on 100 parts by weight of the water-absorbent resin. The inorganic oxide is an essential component for securing the strength, particularly the abrasion resistance, of the film-forming solution, but when the content thereof is increased, the antifogging property of the film-forming solution is lowered.

(Fine particles of inorganic oxide)

The film-forming solution may further contain inorganic oxide fine particles as at least a part of the inorganic oxide. The inorganic oxide constituting the inorganic oxide fine particles is, for example, an oxide of at least 1 element selected from Si, ti, zr, ta, nb, nd, la, ce, and Sn, and is preferably silica fine particles. The silica fine particles can be introduced into the film-forming solution by adding colloidal silica, for example. The inorganic oxide fine particles are excellent in the effect of transmitting the stress applied to the film-forming solution to the article supporting the film-forming solution, and also have high hardness. Therefore, the addition of the inorganic oxide fine particles is advantageous from the viewpoint of improving the abrasion resistance of the film forming solution. When the inorganic oxide fine particles are added to the film-forming solution, fine voids are formed in the portions where the fine particles come into contact with or come close to each other, and water vapor is likely to enter the film through the voids. Therefore, the addition of the inorganic oxide fine particles also has an effect of contributing to the improvement of antifogging property. The inorganic oxide fine particles can be supplied to the film-forming solution by adding the inorganic oxide fine particles formed in advance to the coating liquid for forming the film-forming solution.

When the average particle diameter of the inorganic oxide fine particles is too large, the film-forming solution may be cloudy; when too small, aggregation occurs and uniform dispersion becomes difficult. From this viewpoint, the average particle diameter of the inorganic oxide fine particles is preferably 1 to 20nm, more preferably 5 to 20nm. Here, the average particle diameter of the inorganic oxide fine particles is expressed as primary particles. The average particle size of the inorganic oxide fine particles is determined by measuring the particle sizes of 50 arbitrarily selected fine particles by observation with a scanning electron microscope and averaging the measured values. When the content of the inorganic oxide fine particles is increased, the water absorption amount of the entire film-forming solution is decreased, and the film-forming solution may be clouded. The inorganic oxide fine particles are added in an amount of preferably 0 to 50 parts by weight, more preferably 2 to 30 parts by weight, still more preferably 5 to 25 parts by weight, particularly preferably 10 to 20 parts by weight, based on 100 parts by weight of the water-absorbent resin.

(hydrolyzable Metal Compound)

In order to mix the inorganic oxide in the film-forming solution, a metal compound having a hydrolyzable group (hydrolyzable metal compound) or a hydrolysate thereof may be added to the coating liquid for forming the film-forming solution. The hydrolyzable metal compound is preferably a silicon compound having a hydrolyzable group represented by the following formula (I). The silica contained in the inorganic oxide preferably contains silica derived from a silicon compound having a hydrolyzable group or a hydrolysate thereof. The silicon compounds having a hydrolyzable group represented by the formula (I) may be used alone or in combination of 2 or more. In the present invention, silica also includes a compound in which an organic metal is directly bonded to a part of silicon thereof among silicon compounds bonded by siloxane bonds.

R _m SiX _4-m (I)

R in the formula (I) is a hydrocarbon group having 1 to 3 carbon atoms, wherein a hydrogen atom may be substituted with a reactive functional group. Examples of the hydrocarbon group having 1 to 3 carbon atoms include an alkyl group having 1 to 3 carbon atoms (methyl, ethyl, n-propyl, isopropyl) and an alkenyl group having 2 to 3 carbon atoms (vinyl, allyl, propenyl).

The reactive functional group is preferably at least 1 selected from an oxyglycidyl group and an amino group. The hydrolyzable metal compound having a reactive functional group strongly bonds the water-absorbent resin, which is an organic substance, and the silica, which is an inorganic oxide, and contributes to improvement in abrasion resistance, hardness, and the like of the film-forming solution.

X in the formula (I) is a hydrolyzable group or a halogen atom. Examples of the hydrolyzable group include at least 1 selected from the group consisting of an alkoxy group, an acyloxy group, an alkenyloxy group, and an amino group. Examples of the alkoxy group include alkoxy groups having 1 to 4 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group) and the like. Among the hydrolyzable groups, alkoxy groups are preferred, and alkoxy groups having 1 to 4 carbon atoms are more preferred. The halogen atom is, for example, chlorine.

M in the formula (I) is an integer of 0 to 2, preferably an integer of 0 to 1.

A preferable specific example of the silicon compound having a hydrolyzable group represented by the formula (I) is a silicon alkoxide in which X in the formula (I) is an alkoxy group. Further, it is more preferable that the silicon alkoxide contains a compound (SiX) corresponding to m =0 in the formula (I) ₄ ) 4-functional silicon alkoxide. Specific examples of the 4-functional silicon alkoxide include tetramethoxysilane and tetraethoxysilane. The silicon alkoxide may be used alone, or 2 or more kinds may be used in combination, and when 2 or more kinds are used in combination, the main component of the silicon alkoxide is more preferably a 4-functional silicon alkoxide.

More preferably, the silicon alkoxide comprises a 4-functional silicon alkoxide and a compound corresponding to m =1 in formula (I) (RSiX) ₃ ) 3-functional silicon alkoxide. Specific examples of the 3-functional silicon alkoxide having no reactive functional group include methyltriethoxysilane, ethyltriethoxysilane, and n-propyltriethoxysilane. Specific examples of the 3-functional silicon alkoxide having a reactive functional group include glycidoxyalkyltrialkoxysilane (e.g., 3-glycidoxypropyltrimethoxysilane) and aminoalkyltrialkoxysilane (e.g., 3-aminopropyltriethoxysilane).

Silicon alkoxides having reactive functional groups are sometimes referred to as silane coupling agents. A compound corresponding to m =2 in formula (I) (R) ₂ SiX ₂ ) The 2-functional silicon alkoxide of (1) is also a silane coupling agent when at least one of R is a reactive functional group. Specific examples of the 2-functional silicon alkoxide having at least one reactive functional group in R include glycidoxyalkyldialkoxysilane (e.g., 3-glycidoxypropylmethyldimethoxysilane), aminoalkyldialkoxysilane [ N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane ] and the like]And so on.

When the ultraviolet absorber or the infrared absorber is an organic substance, it is particularly preferable that the silicon alkoxide contains a silane coupling agent. This is because the light-shielding property (e.g., ultraviolet-blocking property) by the ultraviolet absorber or the infrared absorber can be improved. The reason why the light-shielding property of the film-forming solution is improved by the silane coupling agent is considered to be that the light-absorbing agent as the organic compound is more uniformly dispersed in the silica-containing water-absorbent resin by adding the silane coupling agent (comparison of examples 1 and 3 or examples 2 and 4 described later).

When hydrolysis and polycondensation of the silicon compound having a hydrolyzable group represented by the formula (I) completely proceed, the component represented by the following formula (II) is provided.

R _m SiO _(4-m)/2 (II)

R and m in formula (II) are as defined above. After the hydrolysis and polycondensation, the compound represented by the formula (II) actually forms a network structure of siloxane bonds (Si-O-Si) in which silicon atoms and oxygen atoms are alternately connected and which expand three-dimensionally in the film-forming solution.

When the content of silica derived from the 4-functional silicon alkoxide or the 3-functional silicon alkoxide in the film-forming solution is increased, the antifogging property of the film-forming solution may be decreased. One of the reasons for this is that the flexibility of the film-forming solution is reduced, and swelling and shrinkage of the film accompanying absorption and release of moisture are restricted. The amount of silica added from the 4-functional silicon alkoxide is preferably in the range of 0 to 30 parts by weight, more preferably 1 to 20 parts by weight, and still more preferably 3 to 10 parts by weight, based on 100 parts by weight of the water-absorbent resin. The amount of silica added from the 3-functional silicon alkoxide is preferably in the range of 0 to 30 parts by weight, more preferably 0.05 to 15 parts by weight, and still more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the water-absorbent resin.

The ultraviolet absorber and the infrared absorber may be the same as the film-forming

solutions

1 and 2.

(crosslinked structure)

The film-forming solution may contain a crosslinked structure derived from at least 1 crosslinking agent selected from the group consisting of an organoboron compound, an organotitanium compound, and an organozirconium compound. The introduction of the crosslinked structure can improve the abrasion resistance and water resistance of the film-forming solution. From another point of view, it is stated that introduction of the crosslinked structure does not lower the antifogging property of the film-forming solution but easily improves the durability thereof.

The crosslinking agent is not particularly limited as long as it can crosslink the water-absorbent resin to be used. Here, the organic titanium compound is exemplified only. The organic titanium compound is, for example, at least 1 selected from the group consisting of titanium alkoxide, titanium chelate compound and titanium acylate. Examples of the titanium alkoxide include titanium tetraisopropoxide, titanium tetra-n-butoxide, and titanium tetraoctyloxide. Examples of the titanium chelate compound include titanium acetylacetonate, titanium ethylacetoacetate, titanium octylene glycol, titanium triethanolamine and titanium lactate. The titanium lactate may be an ammonium salt (titanium ammonium lactate). Examples of the titanium acylate include titanium stearate. Preferred organic titanium compounds are titanium chelates, in particular titanium lactate.

When the water-absorbent resin is a polyvinyl acetal resin, a preferable crosslinking agent is an organic titanium compound, particularly titanium lactate.

(other optional Components)

Other additives may be added to the film-forming solution. The additive may be a glycol such as glycerin or ethylene glycol having a function of improving antifogging properties. The additive may be a surfactant, an interface modifier, a lubricity imparting agent, a leveling agent, a defoaming agent, a preservative, or the like. < 2-4. Coating Process and drying Process >

The coating of the film-forming solution can be carried out by a conventionally known method such as a flow coating method, a dip coating method, a spin coating method, a spray coating method, a roll coating method, a meniscus coating method, a die coating method, and the like.

In the step of coating the film-forming solution, the Relative Humidity (RH) of the atmosphere is preferably kept at less than 40%, and further at 30% or less. While maintaining a low relative humidity, the coated film can be prevented from absorbing excessive moisture from the atmosphere. Once a large amount of moisture is absorbed from the atmosphere, residual water entering the matrix of the membrane may cause the strength of the membrane to decrease.

The temperature for drying the transparent substrate after coating the film-forming solution is 130 ℃ or higher, preferably 160 ℃ or higher, more preferably 170 ℃ or higher, and may be 180 ℃ or higher. From the viewpoint of avoiding decomposition of the ultraviolet absorber, the organic polymer, and the like, the drying temperature is preferably 300 ℃ or lower, particularly 250 ℃ or lower, and may be 200 ℃ or lower.

The drying step preferably includes an air drying step and a heat drying step accompanied by heating. The air-drying step may be performed by exposing the film-forming solution to an atmosphere in which the relative humidity is kept at less than 40%, and further kept at 30% or less. The air-drying step may be performed at room temperature as a non-heating step. In the heat drying step, a dehydration reaction involving silanol groups contained in the hydrolysate of the silicon compound a or the silicon compound B and hydroxyl groups present on the transparent substrate occurs, and the matrix structure (network of Si — O bonds) composed of silicon atoms and oxygen atoms is expanded, whereby the ultraviolet barrier film is fixed on the glass body.

< 2-5. Film thickness >

The thickness of the ultraviolet blocking film is not particularly limited, and may be, for example, 0.5 to 10 μm, preferably 1 to 5 μm. If the thickness of the ultraviolet blocking film exceeds 10 μm, the glass laminate may be yellowed and cracks may be formed in the film. In order to effectively realize the ultraviolet blocking function, the film thickness is preferably uniform, and the uniformity of the film thickness distribution is preferably 70% or less.

The uniformity of the film thickness distribution is a value expressed by a percentage in which the difference between the maximum value and the minimum value of the film thickness is divided by the maximum value in the region of the ultraviolet blocking film except for the region of 20mm in width from the periphery. For example, when the film thickness had a minimum value of 1.5 μm and a maximum value of 4 μm, the uniformity was (4-1.5)/4 × 100=62.5%. Thus, the uniformity is preferably 70% or less. The film thickness can be adjusted by, for example, blowing air to the glass body by an air blower or the like after the film-forming solution is applied.

The ultraviolet blocking film may have a film thickness in a region of the ultraviolet blocking film except for a width of 20mm from the peripheral edge, for example, the film thickness on the lower portion side may be thicker than that on the upper portion side. This can shield ultraviolet rays emitted to the lower portion side of the glass laminate in particular. Such a film thickness distribution can be achieved by a flow coating method.

The ultraviolet ray blocking film may have a film thickness in a region of the ultraviolet ray blocking film except for a width of 20mm from the peripheral edge, and the position having the maximum film thickness (0.5 to 10 μm) may be, for example, a position 10cm or more from the edge of the region. The maximum thickness of the film is preferably 2 to 4 μm. This can particularly improve the ultraviolet blocking function near the center of the glass laminate.

< 3. Optical characteristics of glass laminate

Next, the optical characteristics (ultraviolet transmittance) of the entire glass laminate including the glass body and the ultraviolet blocking film will be described.

The transmittance of light having a wavelength of 400nm of the glass laminate of the present invention is preferably 10% or less, more preferably 8% or less. Further, the transmittance of light having a wavelength of 390nm is preferably less than 1.5%.

Further, the glass laminate of the present invention preferably has an ultraviolet transmittance as follows.

Tuv400≤2.0％ (16)

Tuv400 is as described above. Further, it is more preferable that Tuv400 in the above formula (16) is 1.0% or less.

< 3-1. Visible light transmittance 1 >

In the glass laminate of the present invention, the transmittance of light having a wavelength of 420nm is preferably 20% or more, and more preferably 50% or more. This is because the transmittance of the ultraviolet light is reduced as described above, and when the transmittance exceeds the ultraviolet light region, the transmittance of the light in the visible light region is rapidly increased. In other words, the coloring or the like that obstructs the visual field in the glass plate is reduced. On the other hand, the transmittance of light having a wavelength of 420nm is preferably 85% or less. This is to prevent influence on a person located in the vehicle and deterioration of interior decoration in the vehicle.

< 3-2. Visible light transmittance 2 >

In the glass laminate of the present invention, when Tavg is an average value of the transmittances for light having a wavelength of 450 to 800nm, a difference (hereinafter referred to as sharp cutoff) between a wavelength W1 at which the transmittance of the glass laminate is Tavg × 0.9 and a wavelength W2 at which the transmittance of the glass plate is Tavg × 0.1 is preferably 22nm or less. This is the same as described above in the glass plate.

< 3-3. Near Infrared transmittance >

The glass laminate of the present invention has a transmittance of light having a wavelength of 1500nm of preferably 35% or less, more preferably 30% or less, and particularly preferably 25% or less.

Light having a wavelength of 1500nm is light in the near infrared region, particularly in the near infrared region of sunlight. When the transmittance of such light is 35% or less as described above, near infrared rays of sunlight can be appropriately shielded, and when the glass laminate is used as a window glass of an automobile, a phenomenon that the temperature in the automobile becomes excessively high can be alleviated.

< 3-4. Yellowness index >

The glass laminate of the present invention has a light transmittance based on a CIE standard C light source of JIS K7373: the yellow index YI defined by 2006 preferably satisfies the following formula (17).

YI≤10 (17)

Among them, YI.ltoreq.5 is more preferable. On the other hand, when the yellowness index of the glass body is large, the yellowness index of the glass laminate is also large, and there is a possibility that a person in the vehicle may feel a psychological discomfort such as a feeling of annoyance when looking outside the vehicle.

< 3-5. Blue light reduction effect >

In the glass laminate of the present invention, the glass laminate of JIS T7330: the blue light reduction rate calculated as the reduction rate of the effective radiation intensity when passing through the glass laminate is preferably 35% or more of the effective radiation intensity of annex a of 2000 with respect to the blue light shielding function.

More details are as follows. The blue clipping ratio referred to herein is defined as: the value of the ratio of the effective radiation intensity that decreases by passing through the glass laminate to the effective radiation intensity associated with retinal damage caused by blue light of sunlight (hereinafter referred to as the effective radiation intensity of sunlight) is expressed as a percentage. Specifically, the following method was used.

Using JIS T7330:2000 annex a weighting function associated with the blue shading function. The weighting function calculates the sum of wavelengths from 380 to 550nm to obtain the effective radiation intensity of sunlight. Then, the sum of the product of the spectral transmittance of the glass laminate at each wavelength in the above wavelength region and the weighting function is calculated, and the effective radiation intensity of light transmitted through the glass laminate (hereinafter referred to as the effective radiation intensity of transmitted light) is obtained. Then, the ratio of the effective radiation intensity of the transmitted light to the effective radiation intensity of the solar light is calculated, and the value is subtracted by 1 and converted into a percentage. The percentage thus calculated was defined as the blue light reduction ratio of the glass laminate.

When the blue light reduction ratio is high, glare can be prevented without causing glare when the glass laminate is viewed through the outside. In addition, if the yellow index is high, the blue light reduction rate is also increased.

< 4. Durability of glass laminate

The glass laminate of the present invention preferably has the following abrasion resistance and light resistance (ultraviolet ray resistance) as durability.

< 4-1. Wear resistance >

The abrasion resistance of the glass laminate of the present invention can be evaluated by an abrasion test based on JIS R3221. That is, when the surface of the ultraviolet ray blocking film is abraded 1000 times with a 500g load by a TABER abrasion tester (5050 ABRA manufactured by TABER INDUSTRIES, for example), it is preferable that the ultraviolet ray blocking film is not peeled off from the glass body and the haze ratio after the abrasion test is 5% or less. The haze can be measured, for example, using HZ-1S manufactured by Suga Test Instruments Co., ltd.

< 4-2. Light resistance (ultraviolet resistance) >

The light resistance (ultraviolet ray resistance) can be evaluated by the following test. That is, an ultraviolet irradiation apparatus (EYE SUPER UV TESTER SUV-W13) manufactured by Kawasaki electric corporation was used, and the wavelength of the applied light was 295 to 450nm, and the illuminance was 76mW/cm ² The black panel temperature was 83 ℃ and the humidity was 50% RH, and the surface of the glass laminate on which the ultraviolet ray blocking film was not formed was irradiated with ultraviolet rays for 100 hours. Further, the difference in Tuv400 between the glass laminate before and after irradiation is preferably 2% or less.

< 5. Feature >

According to the present invention, both the glass body and the ultraviolet blocking film have an ultraviolet blocking function, and thus the ultraviolet blocking function of the entire glass laminate can be improved. In particular, in the present invention, the glass body has a Tuv400 of 50% or less, and the transmittance of light having a wavelength of 400nm of the entire glass laminate is 10% or less, and the Tuv400 is 2.0% or less. Therefore, the ultraviolet rays near the upper limit of the ultraviolet region can be reliably shielded.

< 6. Variant

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit thereof. Further, a plurality of modifications shown below can be combined as appropriate.

＜6－1＞

In the above embodiment, the ultraviolet blocking film is formed by coating the film forming solution on the glass body, but the operation may be performed as follows. For example, a film-forming solution or the like is applied to a substrate sheet to form an ultraviolet ray blocking film. Alternatively, an adhesive may be applied to the opposite surface of the substrate sheet and bonded to the surface of the glass body.

Specifically, the ultraviolet blocking film is formed by applying the film-forming solution to a sheet made of a transparent resin such as polyethylene or polyethylene terephthalate. Then, the sheet is attached to the surface of the glass body with an acrylic or silicone adhesive, for example. In this way, the glass laminate of the present invention can be formed.

＜6－2＞

The ultraviolet blocking film may be applied to a desired portion of the glass body without being applied to the entire surface of the glass body. For example, in a sash window used as a side window, a portion where the ultraviolet blocking film is not formed may be provided in at least one of the portions along the upper side and the side edges. This is because the portion is, for example, a portion accommodated in the glass run channel or the like.

＜6－3＞

The ultraviolet ray blocking film may also have antifogging properties. This can provide an ultraviolet blocking function and antifogging performance. Therefore, even when the window glass is easily fogged in rainy weather or the like, dew condensation or the like can be prevented, and a field of view through the window glass can be secured.

Such antifogging property can be achieved by providing the ultraviolet ray blocking film with water absorbing property. This allows water vapor or moisture to be absorbed. Specifically, for example, the ultraviolet ray blocking film may contain a water-absorbent resin. The water-absorbent resin is not particularly limited, and examples thereof include polyethylene glycol, polyether resins, polyurethane resins, starch resins, cellulose resins, acrylic resins, epoxy resins, polyester polyols, hydroxyalkyl celluloses, polyvinyl alcohols, polyvinyl pyrrolidones, polyvinyl acetal resins, and polyvinyl acetates. Among them, preferred are hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal resin, polyvinyl acetate, epoxy resin and polyurethane resin, more preferred are polyvinyl acetal resin, epoxy resin and polyurethane resin, and particularly preferred is polyvinyl acetal resin.

From the viewpoint of film hardness, water absorption, and antifogging property, the content of the water-absorbent resin based on the weight of the ultraviolet ray barrier film is preferably 50 wt% or more, more preferably 60 wt% or more, and particularly preferably 65 wt% or more, and is 95 wt% or less, more preferably 90 wt% or less, and particularly preferably 85 wt% or less.

Further, the surface of the ultraviolet ray blocking film may be subjected to hydrophilic treatment to impart hydrophilicity. This makes it possible to prevent the water condensed on the surface of the ultraviolet ray blocking film from forming a continuous film shape on the surface of the film, thereby preventing the visibility from being obstructed.

＜6－4＞

The ultraviolet ray blocking film can have a performance of ensuring visibility. The visibility securing performance means that the haze ratio of the glass laminate is low in a state where water droplets are generated on the film surface due to condensation. That is, it means that white turbidity is small even if dew condensation occurs. In this case, the larger the water droplets generated by condensation, the smaller the white turbidity and the smaller the haze ratio. On the other hand, the larger the water droplet, the larger the haze ratio.

Further, the surface of the film having such visibility-securing performance is preferably hydrophobic. This reduces the area covered by water droplets of water generated by condensation of the glass body on the film surface, and thus can reduce the haze ratio.

One of the means for providing visibility-securing performance is that the ultraviolet ray blocking film further contains a water repellent group. The water-repelling group preferably includes a linear or cyclic alkyl group having 3 to 30 carbon atoms and a linear or cyclic alkyl group having 1 to 30 carbon atoms wherein a part of the hydrogen atoms is substituted with fluorine, and particularly preferably includes a linear alkyl group having 4 to 8 carbon atoms, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. For example, the ultraviolet ray film can be made to contain a water repellent group by making a film forming solution contain a compound having a water repellent group and a functional group capable of hydrolysis or a halogen atom, and applying the solution to a glass body (or a substrate sheet).

Another means for providing the glass laminate with visibility-securing performance is to further form a visibility-securing film on the ultraviolet ray blocking film, for example. Alternatively, the visibility securing film may be laminated on the side of the glass body opposite to the side on which the ultraviolet blocking film is formed. For example, when the glass body is a laminated glass, a film for ensuring visibility may be formed on the side of any of the glass plates opposite to the side on which the ultraviolet blocking film is laminated.

Specific examples of the film for ensuring visibility are as follows. The visibility-ensuring film contains a water repellent group and a metal oxide component. The film for ensuring visibility may contain other functional components as necessary, and may further contain a resin, for example. The resin contributes to providing flexibility to the film and improving uniformity of hydrophobicity. However, when the content of the resin is too high, the strength of the film may be reduced. Therefore, it is sometimes preferable that the film ensuring visibility does not contain a resin. In particular, when a film for ensuring visibility is formed on the surface of a glass plate that slides with other members in opening and closing of a window glass, the film is preferably free of resin. A typical window glass that slides against another member is a door glass.

(Water repellant group)

The water repellent group makes the surface of the film ensuring visibility hydrophobic, making the surface a surface on which water vapor is hard to condense. Furthermore, depending on the kind of the water repellent base, it is also helpful to ensure rectilinear propagation of incident light even in the case where water droplets are formed on the surface of the film that ensures visibility. The water-repelling group suitable for securing the light-transmitting straight-chain property is a straight-chain alkyl group having 3 to 9 carbon atoms, preferably 4 to 8 carbon atoms, particularly 5 to 8 carbon atoms, and particularly 5 to 7 carbon atoms.

The area of the water droplet covering film formed by condensing the same amount of water vapor on the surface of the film tends to be smaller as the water contact angle of the surface is larger. The smaller the area covered by the water droplets, the less light incident on the film will scatter. The surface of the film for ensuring visibility, in which the water contact angle is increased due to the presence of the water repellent group, is difficult to form water droplets, and even in a state in which water droplets are formed, the area covered with water droplets is relatively small, thus being advantageous in maintaining the straight-line transmissibility of transmitted light.

However, the strength of hydrophobicity and the uniformity of hydrophobicity, both expressed by the water contact angle, affect the straight-line transmissibility of transmitted light. This is because water droplets are formed on the surface of the film surface where the hydrophobic property is not uniform and hydrophilic spots are scattered, starting from water vapor adsorbed by the hydrophilic spots. Therefore, it is preferable that the water repellent group is present in an orientation on the surface of the film so that the surface of the film is uniformly hydrophobic. The water-repellent group which is suitable for being present on the surface of the film in a state of high orientation aligned in the same direction is a straight-chain alkyl group having a certain or more carbon atoms. However, a long linear alkyl group having an excessively large number of carbon atoms is difficult to achieve high orientation because the linear alkyl group is easily bent halfway.

If a perfluoroalkyl group is used, a stronger hydrophobicity can be achieved. However, perfluoroalkyl groups, particularly when the number of carbon atoms is large, tend to be oriented in a polycrystalline manner on the film surface because they are rigid functional groups whose crystallinity is significantly increased. Therefore, a locally low hydrophobic portion is easily generated on the film surface. From the viewpoint of ensuring uniformity of hydrophobicity, a linear alkyl group having the above carbon number is more preferable than a perfluoroalkyl group.

(hydrolyzable Metal Compound having Water repellent group)

In order to incorporate a water repellent group into a film which ensures visibility, a metal compound having a water repellent group (water repellent group-containing metal compound), particularly a metal compound having a water repellent group and a functional group capable of hydrolysis or a halogen atom (water repellent group-containing hydrolyzable metal compound), or a hydrolysate thereof may be added to a coating liquid for forming a film. In other words, the water-repelling group may be derived from a hydrolyzable metal compound containing a water-repelling group. The water repellent group-containing hydrolyzable metal compound is preferably a water repellent group-containing hydrolyzable silicon compound represented by the following formula (I).

R _m SiY _4-m (I)

Herein, R is a water repellent group, specifically a straight-chain alkyl group having 3 to 9 carbon atoms, Y is a hydrolyzable functional group or a halogen atom, and m is an integer of 1 to 3. The hydrolyzable functional group is, for example, at least 1 selected from the group consisting of an alkoxy group, an acyloxy group, an alkenyloxy group and an amino group, and is preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. The alkenyloxy group is, for example, an isopropenyloxy group. The halogen atom is preferably chlorine. The functional group exemplified here may be used as a "hydrolyzable functional group" to be described later. m is preferably 1 or 2.

When hydrolysis and polycondensation of the compound represented by the formula (I) completely proceed, the component represented by the following formula (II) is provided.

R _m SiO _(4-m)/2 (II)

Here, R and m are as described above. After hydrolysis and polycondensation, the compound represented by formula (II) actually forms a network structure in which silicon atoms are connected to each other via an oxygen atom in the film that ensures visibility.

In this way, the compound represented by the formula (I) is hydrolyzed or partially hydrolyzed, and at least a part thereof is further polycondensed to form a network structure of siloxane bonds (Si-O-Si) in which silicon atoms and oxygen atoms are alternately bonded and which are three-dimensionally extended. The water repellent group R is bonded to silicon atoms contained in the network structure. In other words, the water repellent group R is fixed in the network structure of siloxane bonds by R — Si bonds. The structure is favorable for uniformly dispersing the water repellent base R in the film. The network structure may contain a silica component provided by a silicon compound (e.g., tetraalkoxysilane, silane coupling agent) other than the hydrolyzable silicon compound containing a water-repellent group represented by formula (I). When a silicon compound having no water-repelling group and having a functional group or halogen atom that can be hydrolyzed (a hydrolyzable silicon compound having no water-repelling group) is mixed with a hydrolyzable silicon compound having a water-repelling group in a coating liquid for forming a film that ensures visibility, a network structure including siloxane bonds of silicon atoms bonded to the water-repelling group and silicon atoms not bonded to the water-repelling group can be formed. With such a structure, the content of the water repellent group and the content of the metal oxide component in the film for ensuring visibility can be easily adjusted independently of each other.

When a water-repellent group is introduced into a film with ensured visibility by using a water-repellent group-containing hydrolyzable silicon compound (see formula (I)), a strong siloxane bond (Si — O — Si) network structure is formed. The formation of such a network structure is advantageous not only in improving the wear resistance but also in improving the hardness, water resistance, and the like.

The water repellent group may be added to the extent that the water contact angle of the surface of the film ensuring visibility reaches 85 degrees or more, preferably 90 degrees or more, more preferably 95 degrees or more. The water contact angle is a value measured by dropping a 4mg drop of water onto the surface of the film. The upper limit of the water contact angle is not particularly limited, and is, for example, 105 degrees or less, and further 103 degrees or less. It is preferable that the water repellent group is uniformly contained in the visibility-ensuring film so that the above water contact angle reaches the above range in the entire region of the surface of the visibility-ensuring film.

The film for ensuring visibility preferably contains a water repellent group in a range of 1 part by mass or more, preferably 3 parts by mass or more, and more preferably 4 parts by mass or more, and in a range of 50 parts by mass or less, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and sometimes 15 parts by mass or less, with respect to 100 parts by mass of the metal oxide component.

(Metal oxide component)

The visibility-ensuring film contains a metal oxide component. The metal oxide component is, for example, an oxide component of at least 1 element selected from Si, ti, zr, ta, nb, nd, la, ce, and Sn, and is preferably an oxide component of Si (silica component).

At least a part of the metal oxide component may be a metal oxide component derived from a hydrolyzable metal compound or a hydrolysate thereof added to a coating liquid for forming a film for ensuring visibility. Here, the hydrolyzable metal compound is selected from: a) At least 1 of a metal compound having a water-repelling group and a functional group capable of hydrolysis or a halogen atom (hydrolyzable metal compound containing a water-repelling group) and b) a metal compound having no water-repelling group, a functional group capable of hydrolysis or a halogen atom (hydrolyzable metal compound not containing a water-repelling group). The metal oxide component from a) and/or b) is an oxide of a metal atom constituting the hydrolyzable metal compound. The metal oxide component may contain a metal oxide component derived from metal oxide fine particles added to a coating liquid for forming a film for ensuring visibility, and a metal oxide component derived from a hydrolyzable metal compound or a hydrolysate thereof added to the coating liquid. Here, the hydrolyzable metal compound is also at least 1 selected from the group consisting of a) and b). The hydrolyzable metal compound of b) above, i.e., having no water repellent group, may contain at least 1 selected from tetraalkoxysilanes and silane coupling agents. The metal oxide fine particles and b) will be described below in addition to the above a) already described.

(Metal oxide Fine particles)

The film for ensuring visibility may further contain metal oxide fine particles as at least a part of the metal oxide component. The metal oxide constituting the metal oxide fine particles is, for example, an oxide of at least 1 element selected from Si, ti, zr, ta, nb, nd, la, ce, and Sn, and is preferably silica fine particles. The silica fine particles can be introduced into the film by, for example, adding colloidal silica. The metal oxide fine particles are excellent in the function of transmitting the stress applied to the film for ensuring visibility to the transparent article (glass laminate) supporting the film, and also have high hardness. Therefore, the addition of the metal oxide fine particles is advantageous from the viewpoint of improving the abrasion resistance and scratch resistance of the film ensuring visibility. By adding the metal oxide fine particles formed in advance to the coating liquid for forming the film with ensured visibility, the metal oxide fine particles can be supplied to the film with ensured visibility. However, since the metal oxide fine particles may be a factor for forming hydrophilic spots on the surface of the film, it is preferable not to add them to the film unless it is necessary to improve the abrasion resistance. That is, the film ensuring visibility is preferably used in a form not containing metal oxide fine particles unless particular importance is attached to abrasion resistance and the like.

When the average particle diameter of the metal oxide fine particles is too large, the film may be clouded, and when it is too small, the film may be aggregated and it may be difficult to uniformly disperse the particles. From this viewpoint, the metal oxide fine particles preferably have an average particle diameter of 1 to 20nm, particularly 5 to 20nm. Here, the average particle diameter of the metal oxide fine particles is expressed as primary particles. The average particle diameter of the metal oxide fine particles is determined by measuring the particle diameters of arbitrarily selected 50 fine particles by observation with a scanning electron microscope and averaging the measured values. When the content of the metal oxide fine particles is too large, the film may be clouded.

(hydrolyzable Metal Compound having no Water repellent group)

The visibility-ensuring film may contain a metal oxide component from a hydrolyzable metal compound that does not have a water repellent group (does not contain a hydrolyzable compound that does not have a water repellent group). The hydrolyzable metal compound containing no water-repellent group is preferably a hydrolyzable silicon compound having no water-repellent group. The hydrolyzable silicon compound having no water-repelling group is, for example, at least 1 silicon compound selected from the group consisting of silicon alkoxide, chlorosilane, acyloxysilane, alkenyloxysilane, and aminosilane (but not having a water-repelling group), preferably a silicon alkoxide having no water-repelling group. Among them, as the alkenyloxysilane, isopropenyloxysilane can be exemplified.

The hydrolyzable silicon compound having no water repellent group may be a compound represented by the following formula (III).

SiY ₄ (III)

As described above, Y is a hydrolyzable functional group, and is preferably at least 1 selected from alkoxy, acyloxy, alkenyloxy, amino, and halogen atoms.

A hydrolyzable metal compound containing no water-repellent group is hydrolyzed or partially hydrolyzed, and at least a part thereof is polycondensed to provide a metal oxide component in which metal atoms are bonded to oxygen atoms. This component firmly bonds the metal oxide fine particles and the resin, and contributes to improvement in abrasion resistance, hardness, water resistance, and the like of the film that ensures visibility.

A preferable example of the hydrolyzable silicon compound having no water repellent group is tetraalkoxysilane, more specifically tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms. The tetraalkoxysilane is, for example, at least 1 selected from tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxysilane.

When the content of the metal oxide (silica) component derived from the tetraalkoxysilane is too large, the hydrophobicity of the film for securing visibility may decrease.

(resin)

The resin is an optional component in the film for ensuring visibility, but when added, it is preferably added in a range of more than 0 part by mass and 50 parts by mass or less with respect to 100 parts by mass of the metal oxide component in order not to decrease the abrasion resistance and the like of the film. The amount of the resin is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and particularly preferably 30 parts by mass or less, per 100 parts by mass of the metal oxide component. The addition of a large amount of resin is a factor of forming hydrophilic spots on the surface of the film, and is therefore desirably avoided. The type of resin is not particularly limited, and a resin having high water absorbability is preferably avoided in order to prevent formation of hydrophilic spots. For example, when a polyvinyl butyral resin is used as the resin, the butyralization degree (acetalization degree) is preferably 50 mol% or more, particularly preferably 55 mol% or more, and more preferably 60 mol% or more. The upper limit of the butyralation degree is not particularly limited, and may be 85 mol% or less.

(other optional ingredients)

Other additives may be incorporated into the visibility-securing film. The additive may be glycols, surfactants, leveling agents, ultraviolet absorbers, colorants, antifoaming agents, preservatives, and the like.

(film thickness)

The film for ensuring visibility preferably has a film thickness of 3 to 70nm, preferably 5 to 50nm, more preferably 7 to 45m, and particularly preferably 10 to 40nm.

(film formation)

A film with ensured visibility can be formed by applying a coating liquid to a glass laminate such as a transparent substrate and drying the applied coating liquid. The drying of the coating liquid may be accompanied by heating. The solvent used for the preparation of the coating liquid and the coating method of the coating liquid can use conventionally known materials and methods.

In the coating step of the coating liquid, the relative humidity of the atmosphere is preferably kept at less than 40%, and further kept at 30% or less. While maintaining a low relative humidity, the film is prevented from absorbing excess moisture from the atmosphere. Once a large amount of moisture is absorbed from the atmosphere, residual water that enters the matrix of the membrane may cause the strength of the membrane to decrease.

Preferably, the drying step of the coating liquid includes an air drying step and a heating and drying step accompanied by heating. The air-drying step may be performed by exposing the coating liquid to an atmosphere in which the relative humidity is kept at less than 40%, and further at 30% or less. The air-drying step may be a non-heating step, in other words, may be performed at room temperature. When the coating liquid contains a hydrolyzable silicon compound, a dehydration reaction occurs in which silanol groups contained in the hydrolyzate of the silicon compound or the like and hydroxyl groups present on the glass laminate participate, and the matrix structure (network of Si — O bonds) composed of silicon atoms and oxygen atoms is extended in the heat drying step.

The heating temperature in the heating and drying step is preferably 300 ℃ or lower, for example, 100 to 200 ℃, and the heating time is preferably 1 minute to 1 hour.

The glass laminate may further have a low reflection film. The low reflection film may be formed on the ultraviolet blocking film, or may be formed on a surface of the glass body opposite to the surface on which the ultraviolet blocking film is formed. In the case where the glass body is a laminated glass, the low reflection film may be formed on the surface of any of the glass plates opposite to the surface on which the ultraviolet blocking film is formed. Specific examples of the low reflection film are as follows. The following mainly describes an example in which a low reflection film is formed on a glass body, but basically the same applies to the case in which the low reflection film is formed on an ultraviolet blocking film.

For example, the low reflection film contains silica fine particles and a binder at a weight ratio of 60: 40 to 95: 5, respectively. The low reflection film is formed by mixing (1) raw material fine particles composed of non-aggregated silica fine particles having an average particle diameter of 40 to 1000nm and at least one of chain-like aggregated silica fine particles having an average primary particle diameter of 10 to 100nm, (2) a hydrolyzable metal compound, (3) water and (4) a solvent, hydrolyzing the hydrolyzable metal compound in the presence of the raw material fine particles to prepare a coating liquid, covering a glass body or an ultraviolet ray blocking film with the coating liquid, and heating the coating liquid.

The silica fine particles used herein can be prepared by any preparation method, and examples thereof include silica fine particles synthesized by reacting a silicon alkoxide with a basic catalyst such as ammonia by a sol-gel method, colloidal silica using sodium silicate or the like as a raw material, fumed silica synthesized in a gas phase, and the like. The structure of the obtained low reflection film greatly changes depending on the particle diameter of the silica fine particles. When the particle size of the silica fine particles is too small, the size of voids formed between particles in the low reflection film is reduced, capillary force is increased, and the attached dirt is hard to be removed, or moisture and organic matter in the air gradually enter the voids, and thus the reflectance is increased with time. Further, since the amount of the binder used for bonding the silica microparticles to each other and the silica microparticles to the glass body is not limited to the upper limit as described later, when the particle diameter of the silica microparticles is too small, the surface area of the microparticles is relatively increased, and the amount of the binder reacting with the surface may become insufficient, and as a result, the adhesive force of the film may be weakened. When the silica fine particle size (primary particle size) is too small, the value of roughness of the surface of the formed film or the internal porosity of the film (the ratio of the space between the silica fine particles not filled with the binder to the volume of the film) decreases, and the apparent refractive index increases. Therefore, in order to (1) facilitate removal of the dirt on the low reflection film, (2) improve the film strength, and (3) reduce the apparent refractive index so as to approach a value (about 1.22) of the square root of the refractive index (about 1.5) of the glass body covered with the low reflection film, the average primary particle diameter of the silica fine particles (refractive index of about 1.45) is preferably 40nm or more, and more preferably 50nm or more. When the particle size of the silica fine particles is too large, scattering of light is intense, and adhesion to the glass body is also reduced. In applications where transparency is required, that is, applications where a low haze ratio, for example, a haze ratio of 1% or less is desired, for example, windows for vehicles and buildings, the average particle diameter of the silica fine particles is preferably 500nm or less, and more preferably 300nm or less. The silica fine particles have an average particle diameter of preferably 50 to 200nm, more preferably 70 to 160nm.

The average particle diameter of the silica fine particles as the raw material fine particles is defined as an arithmetic average d of the number of fine particles (n = 100) obtained by the following equation (1) by actually measuring the diameters (average of the major axis and the minor axis) of primary particles (each primary particle when aggregated to form a chain-like secondary particle) in a planar field of view with a transmission electron microscope of 1 to 5 ten thousand times. Therefore, the measured value is different from the particle diameter obtained by the BET method shown in colloidal silica or the like. The sphericity of the silica particles is represented by an average value of 100 particles of the ratio of the length of the major axis to the length of the minor axis of each particle. The standard deviation of the particle diameter of the fine particles, which represents the particle size distribution of the fine particles, is determined from the diameters by the following numerical expressions (2) and (3).

Wherein n =100 in each formula.

Standard deviation = (d + sigma)/d (3)

When the sphericity of the silica fine particles is 1.0 to 1.2, a low reflection film having an improved degree of filling with fine particles is formed, and the mechanical strength of the film is preferably increased. More preferably, the sphericity is 1.0 to 1.1. In addition, when silica fine particles having a uniform particle diameter are used, the voids between the fine particles can be increased, and therefore the apparent refractive index of the film can be decreased, and the reflectance can be decreased. Therefore, the standard deviation of the particle diameter, which represents the particle size distribution of the silica fine particles, is preferably 1.0 to 1.5, more preferably 1.0 to 1.3, and still more preferably 1.0 to 1.1.

As the non-aggregated silica fine particles having an average particle diameter of 40 to 1000nm, commercially available products such as "SNOWTEX OL", "SNOWTEX YL", "SNOWTEX ZL" manufactured by Nissan chemical Co., ltd, "SEAHOSTAR KE-W10", "SEAHOSTAR KE-W20", "SEAHOSTAR KE-W30", "SEAHOSTAR KE-W50", "SEAHOSTAR KE-E70", "SEAHOSTAR KE-E90" manufactured by Nissan catalyst, etc. are preferable. A silica fine particle dispersion liquid in which silica fine particles are dispersed in a solvent is preferable because handling is easy. As the dispersion medium, there are water, alcohols, cellosolves, glycols and the like, and silica fine particle dispersions dispersed in these dispersion media are commercially available. Further, the fine silica particle powder may be dispersed in these dispersion media.

In the case where a plurality of fine particles are aggregated to form aggregated fine particles (secondary fine particles), the average particle diameter of each fine particle (primary fine particle) constituting the aggregated fine particles is defined as an average primary particle diameter. When the fine particles are aggregated in a chain shape without branches or in a chain shape with branches (chain aggregated fine particles), each fine particle is fixed while maintaining its aggregated state at the time of forming a film, and thus the volume of the film is increased, and the value of the roughness of the irregularities on the surface of the formed film and the porosity inside the film are larger than those of non-aggregated silica fine particles having the same average particle diameter as the average primary particle diameter of the chain aggregated fine particles. Therefore, the chain-like aggregated silica fine particles may have an average primary particle diameter of less than 40nm, and chain-like aggregated silica fine particles having an average primary particle diameter d of 10 to 100nm may be used. The chain-like aggregated silica fine particles preferably have an average length (L) of 60 to 500nm and an average length-to-average primary particle diameter ratio (L/d) of 3 to 20. Examples of the chain-like aggregated silica fine particles include "SNOWTEX OUP" and "SNOWTEX UP" manufactured by nippon chemical corporation.

The coating liquid for forming a low reflection film can be prepared by hydrolyzing a metal compound capable of being hydrolyzed in the presence of silica fine particles, and the mechanical strength of the resulting film is significantly improved. In the case of the present invention in which the metal compound is hydrolyzed in the presence of the silica fine particles, since the condensation reaction between the product generated by the hydrolysis and silanol present on the surface of the fine particles occurs at substantially the same time as the hydrolysis, (1) the reactivity of the surface of the fine particles is improved by the condensation reaction with the binder component, (2) and the surface of the silica fine particles is covered with the binder by the progress of the condensation reaction, the binder can be effectively used for improving the adhesion between the silica fine particles and the glass body. On the other hand, if the hydrolysis of the metal compound is carried out in a state where fine particles are not present, the binder component is polymerized due to a condensation reaction between the hydrolysis products. When the polymer-converted binder component is mixed with silica microparticles to prepare a coating liquid, (1) condensation reaction between the binder component and the silica microparticles hardly occurs, and thus reactivity on the microparticle surface is lost, and (2) the surface of the silica microparticles is hardly covered with the binder. Therefore, when the adhesion between the glass and the silica fine particles is to be improved as in the former case, a larger amount of the binder component is required.

The binder used here contains, for example, a metal oxide, and preferably at least 1 metal oxide selected from silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, and tantalum oxide is used. The weight ratio of the silica fine particles forming the low reflection film to the binder is in the range of 60: 40 to 95: 5. When the amount of the binder is more than this range, the fine particles are filled with the binder, and the roughness value formed by the fine particles or the porosity in the film is decreased, so that the antireflection effect is lowered. When the binder amount is less than this range, the adhesion force between the fine particles and the glass body and between the fine particles is reduced, and the mechanical strength of the film is weakened. The weight ratio of the silica fine particles to the binder is more preferably 65: 35 to 85: 15 in view of the balance of the reflectance and the film strength. The binder preferably covers the entire surface of the silica fine particles, and the thickness of the binder is preferably 1 to 100nm and 2 to 9% of the average particle diameter of the silica fine particles.

As the metal compound which can be hydrolyzed and becomes a raw material of the binder, metal alkoxides of Si, al, ti, zr, and Ta are preferable in view of film strength, chemical stability, and the like. Among these metal alkoxides, silicon tetraalkoxide, aluminum trialkoxide, titanium tetraalkoxide, and zirconium tetraalkoxide are preferably used, and methoxide, ethoxide, propoxide, and butoxide are particularly preferably used. Particularly in a film containing a large amount of the binder component, the refractive index of the binder component affects the reflectance, and therefore, a silanolate having a small refractive index, particularly, a tetraalkoxysilane or an oligomer thereof is most preferable. In addition, a plurality of metal alkoxides may be mixed and used as the binder component. Except for the metal alkoxide, as long as M (OH) can be obtained by hydrolysis _n The reaction product of (3) is not limited, and examples thereof include a metal halide and a metal compound having an isocyanate group, an acyloxy group, an aminoxy group, and the like. In addition, R, for example, as one of silanolates ¹ _n M(OR ² ) _4-n A compound represented by the formula (M is a silicon atom, R ¹ Is an organic functional group such as alkyl, amino, epoxy, phenyl, methacryloxy and the like, R ² For example, an alkyl group, and n is an integer of 1 to 3) may be used as a binder raw material. In the use of the above-mentioned R ¹ _n M(OR ² ) _4-n In the case of the compound shown above, since an organic residue remains in the gel film after coating, when the compound is used as a binder material in its entirety, the organic residue forms nano-order fine pores after heat treatment, and since the fine pores have a small diameter, the capillary force increases, attached dirt is not easily removed, or dirt, water or the like enters into the fine pores, and the reflectance changes with time, which causes problems, and the film strength is also weakened, it is preferable that R is mentioned above ¹ _n M(OR ² ) _4-n The compounds shown are not used in large amounts, e.g. in terms of metal oxides, but are limited to bindersWithin 50 wt.% of the total amount.

The haze ratio of the glass laminate coated with the low reflection film is a value obtained by combining the haze ratio of the glass body and the haze ratio of the low reflection film, and as the glass body of the present invention, a glass body having a haze ratio as small as possible, for example, a haze ratio of 0.1% or less can be used. Therefore, the haze ratio of the glass laminate of the present invention is substantially equal to that of the low reflection film. The haze ratio of the low reflection film is preferably adjusted to an optimum range depending on the use. For example, in the case of an automobile window, the haze ratio is preferably low from the viewpoint of safety, and the haze ratio of the low reflection glass laminate is 1% or less, more preferably 0.5% or less.

In order to reduce the reflectance of the low reflection film, it is preferable that the surface of the low reflection film is covered with silica fine particles (hereinafter, may be simply referred to as "fine particles") whose surface is covered with a binder. When a layer of fine particles having the same particle size are densely packed in a glass body, the occupied area of the fine particles viewed from the upper part is theoretically about 90%. In order to obtain low reflection performance, the occupied area in the low reflection film in which only one layer of fine particles is formed is preferably 50% or more, more preferably 70% or more. If the occupied area is less than 50%, the surface of the glass body is exposed, and the difference in refractive index between the glass and air causes strong reflection, so that reflection cannot be reduced. The low reflection film may be formed by arranging only one layer of fine particles on the upper surface of the glass, or may be formed by stacking fine particles in multiple stages. In both the 1-layer and multi-layer structure, voids corresponding to the diameters of the particles are formed in the gaps between the glass body and the particles or between the particles, and the voids are effective for reducing the apparent refractive index. When the film is observed from directly above the film by an electron microscope, the total number of fine particles arranged in a plane on the outermost surface of the film and the number of fine particles slightly visible from the gaps between the fine particles on the outermost surface on the lower side of the fine particles on the outermost surface are 30 to 3000 in the area of a square of 1 μm × 1 μm in the case of using non-aggregated silica fine particles having an average particle size of 40 to 500nm as raw material fine particles, and these fine particles preferably have an average particle size of 40 to 500 nm. As described aboveThe total number is more preferably 100 or more and 1000 or less. When non-aggregated silica fine particles having an average particle size of 100 to 1000nm are used as the raw material fine particles, the total number of the fine particles is 10 to 50000 in an area of a square of 10 μm × 10 μm, and these fine particles preferably have an average particle size of 100 to 1000 nm. The total number is more preferably 20 or more and 25000 or less. The particle density depends on the size of the particles, with larger particle diameters having smaller values and smaller particle diameters having larger values. From the viewpoint of improving the film strength, it is more preferable that the fine particles are closely adhered to each other via the adhesive, as compared with the case where the fine particles are carried on a glass plate alone. For example, when the average particle diameter of the fine particles is Dnm, the number of fine particles observed from the right above with an electron microscope in a square film of 10. Mu. M.times.10 μm is preferably 5,000,000/D ² ～10,000,000/D ² And (4) respectively.

The average thickness of the low reflection film of the present invention is defined as follows. A photograph for observing the cross section of the film at a magnification of 5 ten thousand times by an electron microscope was prepared. The length of 10cm (substantially 2 μm) in the electron micrograph was arbitrarily selected, 12 positions were selected in order from the largest convex portion of the film, and the average thickness was determined as the average height from the surface of the glass body of 10 convex portions from the 3 rd to the 12 th positions from the largest number. When the diameter of the used particles is large or when 12 convex parts cannot be selected because the particles are sparsely present, the magnification of the electron microscope is gradually reduced from 5 ten thousand times so that 12 convex parts can be selected, and the average thickness is determined by the above method. The film having an average thickness in the range of 90nm to 180nm can reduce the reflectance in the visible light region most. The value of the physical thickness d defined by the optical thickness (n.d) is smaller than the average thickness, and the value of the physical thickness d corresponding to the average thickness of 90 to 180nm is 80 to 140nm. This is because the interference condition of the reflected light at the interface between the glass and the film and at the interface between the film and the air is satisfied. This interference condition is also satisfied when the thickness is 2n-1 times (n is a natural number) the thickness described above, and therefore, even if the thickness is 3 times or more, the reflectance is lowered, but the strength of the film is lowered, which is not preferable.

On the other hand, when a region spanning both visible light (400 to 780 nm) and infrared light (780 nm to 1.5 μm) is considered as a region where reflectance needs to be reduced, the average thickness of the low reflection film is preferably 90nm to 350 nm. This corresponds to a physical thickness d of 80nm to 300nm.

In particular, in a windshield for an automobile, since the installation angle (the inclination angle from the vertical plane) is about 60 degrees, a film design according to the method of use thereof is required. The surface reflectance (excluding back surface reflection) of soda lime glass having a refractive index of 1.52 is 4.2% at an incident angle of 12 degrees, but is 9% or more at an incident angle of 60 degrees, which corresponds to an incident angle of incident light from a direction horizontal to a windshield mounted on an automobile. The low-reflection film including the fine particles and the binder is similar to a film having one layer including an average refractive index including voids, but the low-reflection performance can be achieved by shifting the optical path difference of the reflected light by half a wavelength by utilizing the interference action of the reflected light at the glass-low-reflection film interface and the reflected light at the low-reflection film-air interface. When the incident angle to the glass with a low reflection film is increased, the optical path difference is shifted in a direction to decrease, and therefore, the optical thickness (nd) of the low reflection film needs to be increased as compared with the reflection at normal incidence. In order to reduce the reflectance at 60 degrees incidence, the optical thickness is preferably designed to be about 140nm to 250 nm. The surface reflectance at an incident angle of 60 degrees largely depends on the apparent refractive index and optical thickness of the low-reflection film, and is 6% or less, preferably 5% or less, and more preferably 4% or less.

In the present invention, the coating liquid for the low reflection film is prepared by mixing silica fine particles, a metal compound capable of hydrolysis, a catalyst for hydrolysis, water, and a solvent and hydrolyzing the mixture. For example, the reaction can be carried out by stirring at room temperature for 1 to 24 hours, or at a temperature higher than room temperature, for example, 40 to 80 ℃ for 10 to 50 minutes. The obtained coating liquid may be diluted with an appropriate solvent in accordance with the coating method to be performed later.

As the hydrolysis catalyst, an acid catalyst is most effective, and an inorganic acid such as hydrochloric acid or nitric acid, acetic acid, or the like can be exemplified. In the presence of an acid catalystIn the case of the agent, the polycondensation reaction is slower than the hydrolysis reaction of a metal compound capable of hydrolysis, such as a metal alkoxide, to form a large amount of hydrolysis reaction product M (OH) _n It is preferable because it can effectively function as a binder. When a basic catalyst is used, the polycondensation reaction rate is higher than the hydrolysis reaction rate, and thus the metal alkoxide forms a reaction product in fine particles for the particle size growth of the silica fine particles originally present, and as a result, the action of the metal alkoxide as a binder is weakened. The content of the catalyst is preferably 0.001 to 4 in terms of a molar ratio relative to the metal compound as the binder.

The amount of water added for hydrolysis of the metal compound may be 0.1 to 100 in terms of a molar ratio relative to the metal compound. When the amount of water added is less than 0.1 in terms of a molar ratio, the acceleration of hydrolysis of the metal compound is insufficient; on the other hand, when the molar ratio is more than 100, the liquid stability tends to be lowered, which is not preferable.

When the chlorine group-containing compound is used as the metal compound, it is not necessary to add a catalyst. The chlorine group-containing compound can undergo hydrolysis reaction without a catalyst. However, the supplementary addition of acid is not problematic.

The solvent may be basically any solvent as long as it can substantially dissolve the metal compound, but is most preferably alcohols such as methanol, ethanol, propanol and butanol, cellosolves such as ethyl cellosolve, butyl cellosolve and propyl cellosolve, glycols such as ethylene glycol, propylene glycol and hexylene glycol. When the concentration of the metal compound dissolved in the solvent is too high, the concentration is preferably 20 wt% or less, and preferably 1 to 20 wt%, because sufficient voids cannot be formed between the fine particles in the film, although the concentration also depends on the amount of the silica fine particles to be dispersed. The amount of the silica fine particles in the coating liquid and the amount of the metal compound (each in terms of SiO as a metal oxide) ₂ 、Al ₂ O ₃ 、TiO ₂ 、ZrO ₂ 、Ta ₂ O ₅ ) The ratio of (B) is preferably 60: 40 to 95: 5 in terms of weight ratio, more preferably 60: 40 to 95: 565∶35～85∶15。

The preferred raw material blending ratios of the coating liquid of the present invention are shown in table 1 below.

[ Table 1]

The coating liquid is applied to a glass body (or an ultraviolet-blocking film, the same applies hereinafter) and heated to cause dehydration condensation reaction of the metal compound hydrolysate and vaporization and combustion of volatile components, thereby forming a low reflection film on a glass substrate.

The coating method may be any known technique, and is not particularly limited, and a method using an apparatus such as a spin coater, a roll coater, a spray coater, or a curtain coater, a method such as a dip coating method (dip coating method) or a Flow coating method (Flow coating method), or various printing methods such as screen printing, gravure printing, or flexographic printing may be used. In particular, when a coating method requiring a high boiling point solvent, for example, a printing method such as flexography or gravure, is used, the glycols are effective solvents, and the reason is not clear, but the glycols can suppress aggregation of fine particles, and are suitable solvents for producing a low reflection film having a small haze. The weight ratio of the glycol contained in the coating liquid may be 5% to 80%.

Depending on the glass body, the glass body may repel the coating liquid or the like and may not be uniformly coated, but this can be improved by cleaning or surface modification of the substrate surface. Examples of the method for cleaning or surface modification include degreasing cleaning with an organic solvent such as alcohol, acetone, or hexane, cleaning with an alkali or an acid, a method for polishing a surface with a polishing agent, ultrasonic cleaning, ultraviolet irradiation treatment, ultraviolet ozone treatment, and plasma treatment.

The heat treatment after coating is an effective method for improving the adhesion between the film containing the silica fine particles and the binder and the glass body. The maximum temperature of the treatment is 200 ℃ or higher, preferably 400 ℃ or higher, more preferably 600 ℃ or higher, and 1800 ℃ or lower. When the temperature is 200 ℃ or higher, the solvent component of the coating liquid evaporates, and the film gelates, resulting in adhesive strength. Further, when the temperature is 400 ℃ or higher, the organic component remaining in the film is almost completely eliminated by burning. When the temperature is 600 ℃ or higher, the condensation reaction between the remaining unreacted silanol groups and the hydrolyzable groups of the hydrolyzate of the metal compound is substantially completed, and the film is densified, whereby the film strength is further improved. The heating time is preferably 5 seconds to 5 hours, more preferably 30 seconds to 1 hour.

Examples

Examples of the present invention are explained below. However, the present invention is not limited to the following examples.

Glass laminates according to examples 1 to 11 and glass laminates according to comparative examples were prepared as shown in table 1 below.

[ Table 2]

More specifically, as described below, for comparative examples and examples 1 to 11, a film forming solution for an ultraviolet absorber was prepared and applied to each of the glass bodies described above, thereby forming an ultraviolet blocking film.

Comparative example

6.500 parts by mass of 2,2', 4' -tetrahydroxybenzophenone (manufactured by BASF corporation, UVINUL 3050), 17.622 parts by mass of tetraethoxysilane (manufactured by Moore chemical Co., ltd.), 3-glycidoxypropyltrimethoxysilane (manufactured by shin-Etsu chemical Co., ltd., KBM-403) 13.312 parts by mass, 2.5 parts by mass of an ITO fine particle dispersion containing 40% by mass of fine particles composed of indium tin oxide (Mitsubishi Materials Electronic Chemicals Co., ltd.), and 0.218 part by mass of polypropylene glycol (Kishida chemical, manufactured by PPG 700), 0.025 part by mass of concentrated nitric acid (manufactured by Binetleaf chemical Co., ltd., concentration), 42.028 part by mass of ethanol as a solvent, 28.125 parts by mass of water (wherein the ethanol and water include a dispersion medium of the fine particle dispersion and water contained in PPG), were mixed and stirred to form a barrier film.

Next, as a glass body, a usual transparent float glass plate (manufactured by Nippon trigger Co., ltd., thickness: 3.1 mm) cut in a 60cm square was washed, and a film-forming solution was applied to the glass plate by a flow coating method under an environment of 20 ℃ and 30% RH. After drying for 5 minutes in the same atmosphere, the glass plate coated with the film-forming solution was dried at 180 ℃ to prepare a glass laminate having an ultraviolet ray blocking film.

(example 1)

A film-forming solution was obtained in the same manner as in comparative example 1, except that the ultraviolet absorber used in the comparative example was changed to 6.000 parts by mass.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that UV-blocking green glass (3.4 mm thick, manufactured by NIPPON NITRILE CORPORATION) was used in place of the transparent float glass of comparative example.

(example 2)

A film-forming solution was obtained in the same manner as in comparative example except that the ultraviolet absorber used in comparative example 1 was changed to 7.00 parts by mass.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that a laminated glass plate (a laminated glass plate obtained by sandwiching a commercially available common intermediate film for laminated glass (Saflex, thickness 0.76 mm) by a transparent float plate glass (manufactured by Japan panel nit corporation) having a thickness of 2.1mm and heat-pressing the interlayer film) was used instead of the transparent float plate glass of comparative example.

(example 3)

The same film-forming solution as in comparative example was obtained.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that dark float plate glass (Legart 50, manufactured by Nippon Denko Co., ltd., thickness 3.4 mm) was used in place of the clear float plate glass of comparative example.

(example 4)

A dispersion (solid content concentration: 10% by weight, average particle diameter: 110 nm) containing as a dispersion a benzotriazole-based ultraviolet absorber (TINUVIN 360, produced by Ciba Specialty Chemicals) in which R1 and R2 in formula (8) are both 1, 3-tetramethylbutyl group and water as a dispersion medium was prepared. Among them, the benzotriazole-based ultraviolet absorber is used as a material obtained by mixing and pulverizing zirconia beads in advance with a paint conditioner so as to have the above average particle diameter.

This ultraviolet absorber dispersion liquid 40.0 parts by mass, tetraethoxysilane 31.25 parts by mass, G-300 (triol obtained by adding propylene oxide to glycerin and having an average molecular weight of 300) manufactured by ADEKA 0.50 parts by mass, concentrated hydrochloric acid (35% by mass concentration, manufactured by kanto chemical corporation) 0.05 parts by mass, ethanol 17.64 parts by mass as a solvent, and water 30.56 parts by mass (wherein ethanol and water include a dispersion medium of the fine particle dispersion liquid and water contained in the concentrated hydrochloric acid) were mixed and stirred to obtain an ultraviolet barrier film-forming solution.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that dark float glass (Galaxsee, manufactured by Nippon Denko K.K. having a thickness of 3.1 mm) was used in place of the clear float glass of comparative example.

(example 5)

A film-forming solution was obtained in the same manner as in example 4, except that the ultraviolet absorber dispersion liquid of example 4 was changed to 30.0 parts by mass. Then, a glass laminate having an ultraviolet ray blocking film was produced in the same manner as in example 4, except that deep-colored float glass (Legart 20, manufactured by Nippon Denko Co., ltd., thickness 3.1 mm) different from that of example 4 was used.

(example 6)

An ultraviolet absorber dispersion liquid of 25.0 parts by mass, tetraethoxysilane 31.2 parts by mass, 3-glycidoxypropyltrimethoxysilane 3.54 parts by mass, and ITO fine particle dispersion liquid of comparative example 5 parts by mass, and Solsperse 41000 (polyether phosphate ester polymer 0.55 parts by mass, concentrated hydrochloric acid 0.071 part by mass, example 4 as a solvent, ethanol 17.4 parts by mass, and water 29.7 parts by mass (wherein ethanol and water include a dispersion medium of the fine particle dispersion liquid and water contained in the concentrated hydrochloric acid) manufactured by Lubrizol corporation of Japan were mixed and stirred to obtain an ultraviolet blocking film forming solution.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example 1, except that UV-blocking green sheet glass (thickness 3.1mm, manufactured by NIPPON NITRILE CORPORATION) was used in place of the transparent float sheet glass of comparative example.

(example 7)

As an ultraviolet absorber, a commercially available antioxidant (copper thiophenol complex derivative; (bis (4-morpholinosulfonyl-1, 2-dithiol) copper tetra-n-butylammonium) having a structural formula in which Bu in formula (15) is an n-butyl group; EST-5, manufactured by Sumitomo Seiko corporation) and a dispersion liquid containing water as a dispersion medium (the content of the copper complex is 10% by weight, and the average particle diameter is 135 nm) were prepared in the same manner as in example 4.

20 parts by mass of the ultraviolet absorber dispersion,

Tetraethoxysilane 13.9 parts by mass,

An ITO fine particle dispersion containing 40 mass% of fine particles composed of indium tin oxide (manufactured by Mitsubishi Materials Electronic Chemicals Co., ltd.) in an amount of 5 parts by mass, 3-glycidoxypropyltrimethoxysilane-free, and,

Solsperse 41000 of example 6 0.1 part by mass

Concentrated hydrochloric acid 0.07 part by mass of example 4

As a solvent,

22.6 parts by mass of ethanol, and

38.4 parts by mass of water (wherein ethanol and water include the dispersion medium of the fine particle dispersion and water contained in concentrated hydrochloric acid) was mixed and stirred to obtain a solution for forming the ultraviolet ray blocking film.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that green plate glass (3.1 mm thick, manufactured by Nippon Denko Co., ltd.) was used instead of the transparent float plate glass of comparative example.

(example 8)

1.0 part by mass of an ultraviolet absorber, 0.69 part by mass of tetraethoxysilane, 62.5 parts by mass of S-LEC KX-5 (a solution containing a polyvinyl acetal resin having a solid content of 8% by mass and containing a degree of acetalization derived from benzaldehyde, and a degree of acetalization of 9 mol%) manufactured by shin-Etsu chemical Co., ltd., the same as in comparative example, 0.05 part by mass of nitric acid, 18.62 parts by mass of an alcohol as a solvent, and 17.63 parts by mass of water were mixed and stirred to obtain an ultraviolet ray barrier film forming solution.

A glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example, except that the same UV-blocking green sheet glass as in example 6 was used instead of the transparent float sheet glass of comparative example.

(example 9)

30.0 parts by mass of the same ultraviolet absorber as in example 4, 1.04 parts by mass of tetraethoxysilane, n-hexyltrimethoxysilane (HTMS, 0.37 parts by mass of "KBM-3063" manufactured by shin-Etsu Silicone Co., ltd., S-LEC KX-5 (a solution containing a polyvinyl acetal resin having a solid content of 8% by mass and containing an acetalization degree derived from benzaldehyde of 9 mol%) 62.5 parts by mass of nitric acid, 10.82 parts by mass of an alcohol as a solvent, and 10.22 parts by mass of water were mixed and stirred to obtain an ultraviolet barrier film-forming solution.

Then, a glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example except that the same dark float plate glass (Galaxsee, manufactured by Nippon Kaisha having a thickness of 3.1 mm) as in example 4 was used in place of the clear float plate glass of comparative example.

(example 10)

A film-forming solution was obtained in the same manner as in example 8, except that the ultraviolet absorber dispersion liquid of example 7 was changed to 20.0 parts by mass. Then, a glass laminate having an ultraviolet ray blocking film was produced in the same manner as in comparative example, except that the same laminated glass plate as in example 2 was used instead of the transparent float glass plate of comparative example.

(example 11)

A sample in which a film for ensuring visibility was further formed on example 1 was used as example 11. The preparation method is specifically as follows. A coating liquid for film formation was prepared, which had a visibility of n-hexyltrimethoxysilane (HTMS, KBM-3063 available from shin-Etsu Silicone Co., ltd.) (0.03 mass%), tetraethoxysilane (TEOS, KBM-04 available from shin-Etsu Silicone Co., ltd.) (0.3 mass%), purified water (0.15 mass%), hydrochloric acid (0.2 mass%) as an acid catalyst, and an Alcohol solvent (SOLMIX AP-7 available from Japan Alcohol corporation) (see-through Silicone Co., ltd.) (0.7 mass%).

Next, the coating liquid was applied on the ultraviolet ray blocking film of example 1 by a flow coating method under an environment of room temperature 20 ℃ and a relative humidity of 30%. After drying the mixture for 10 minutes in the same atmosphere, the mixture was subjected to a heat treatment at 120 ℃ for 20 minutes to prepare example 11.

< 3. Evaluation 1 >

The evaluation shown in tables 3 and 4 below was performed for examples 1 to 11 and comparative examples prepared as described above. The evaluation method is as shown in the embodiment.

[ Table 3]

[ Table 4]

Fig. 7 shows the light transmittances of the respective glass bodies at the respective wavelengths, and shows the glass bodies selected from the glass bodies used in comparative example and examples 1 to 11 in place of the representative glass bodies. Fig. 8 shows the transmittance of light of each wavelength in examples 1,2, 4,6 to 8. Fig. 7 and 8 show only a part of examples and comparative examples, but all the evaluation results are shown in tables 3 and 4.

Referring to fig. 7, the float glass used for the glass body of the comparative example has a higher light transmittance in a wavelength region of 300 to 400nm and a significantly higher Tuv400 of the glass body than other glass bodies. From this, it is considered that the Tuv400 of the glass laminate is high. For example, as shown in FIG. 8, the light transmittance in the wavelength region of 300 to 350nm is almost 0 in the examples, while that in the comparative examples is high. In other examples, although glass bodies having a low Tuv400 content were used, the Tuv400 content of the glass laminate was 2.0% or less in all cases due to the ultraviolet ray blocking film.

In any of the examples, the glass laminate had a Tuv400 of 2.0% or less, but the light transmittance at a wavelength of 420nm was 20% or more, and in particular, examples 2 and 10 were 70% or more. That is, in the embodiment of the present invention, it is possible to sufficiently suppress the transmission of light near the upper limit of the ultraviolet region, and sufficiently transmit visible light having a wavelength of about 400nm or more, and it can be said that the visibility is high.

< 4. Evaluation 2 >

Next, antifogging properties based on water absorption, water contact angle, and straight-line light transmission properties (visibility securing properties) when water droplets are collected were evaluated as follows for the ultraviolet ray blocking films of the glass laminates of examples 8 to 11.

(anti-fogging Property)

The glass laminates of examples 8 to 11 were left to stand at room temperature of 20 ℃ and a relative humidity of 30% for 1 hour. Examples 8 to 11 were placed on a warm water surface having a water temperature of 35 ℃ using a constant temperature water bath, exposed to water vapor, and evaluated by the following criteria, with the time until fogging of the ultraviolet ray blocking film being confirmed.

A: it took 50 seconds or more until fogging was confirmed, and sufficient water absorption property was confirmed.

B: until fogging was confirmed, the fogging was confirmed for more than 30 seconds, but was confirmed within less than 50 seconds, and a certain degree of water absorption was confirmed.

C: fogging was observed in 30 seconds or less, and the water absorption was insufficient.

(contact Angle)

After examples 8 to 11 were left to stand at room temperature of 20 ℃ andbase:Sub>A relative humidity of 30% for 1 hour,base:Sub>A contact angle of about 4 μ L (= 4 mg) ofbase:Sub>A water droplet was dropped on the surface of the ultraviolet ray blocking film usingbase:Sub>A contact angle meter (CA-base:Sub>A) manufactured by synechiae interface science corporation, and the contact angle of the water droplet on the ultraviolet ray blocking film was measured. Then, the water repellency was judged to be possessed if the contact angle was 90 ° or more, and the hydrophilicity was judged to be possessed if the contact angle was 60 ° or less.

(Linear light propagation when Water drops are condensed)

The glass laminates of examples 8 to 11 were left to stand at room temperature of 20 ℃ and a relative humidity of 30% for 1 hour. On the other hand, a constant temperature water tank was used to store warm water kept at a temperature of 40 ℃, examples 8 to 11 were disposed above the warm water, exposed to water vapor, and kept until fogging, that is, condensation of water droplets was confirmed on the front surface of the surface exposed to water vapor. Immediately thereafter, the haze was measured using a haze meter ("HZ-1S" manufactured by Suga Test Instruments Co., ltd.). Then, the straight-line propagation of light when the water droplets condensed was evaluated according to the following criteria.

A: the haze ratio is 15% or less, and the visibility is sufficiently ensured.

B: the haze ratio is more than 15% and 35% or less, and the visibility is ensured to some extent.

C: the haze exceeds 35%, and the visibility securing performance is insufficient.

The straight-line transmissibility of light evaluated as described above represents visibility assurance.

The results are shown in Table 5.

[ Table 5]

	Antifogging property	Contact angle	Visibility securing property
				Comparative example	C		40°	C
Example 8	A	60°	C
				Example 9	A	75°	A
Example 10	A	58°	C
				Example 11	C	100°	A

From the results in table 5, the antifogging property of the comparative examples was low, and fogging occurred in a short time. Therefore, the visibility assurance is also poor. On the other hand, the antifogging properties of examples 8 to 10 were all high, and it took time until fogging was confirmed. On the other hand, in example 11, although the antifogging property was low, the water repellency was exhibited according to the contact angle, and the visibility securing property was high. In examples 8 and 10, although the antifogging property was high, the contact angle showed hydrophilicity and the visibility securing property was low. On the other hand, example 9 showed water repellency and high visibility securing property.

Claims

1. A glass laminate to be mounted on a vehicle, the glass laminate comprising:

a glass body comprising at least 1 glass sheet; and

an ultraviolet blocking film disposed on at least 1 of the glass plates,

the glass body satisfies Tuv400 not more than 50%,

the glass body has a visible light transmittance YA of 70% or more as measured by using a CIE standard illuminant A,

the amount of the 3-valent iron oxide contained per unit area of the glass body is converted into Fe ₂ O ₃ Is 1 to 10mg/cm ² ，

The glass laminate has a transmittance of light having a wavelength of 400nm of 10% or less,

and the glass laminate satisfies Tuv 400. Ltoreq.2.0%.

2. The glass laminate according to claim 1,

the glass laminate has a transmittance of 20% or more for light having a wavelength of 420 nm.

3. The glass laminate according to claim 1 or 2,

when Tavg is an average value of transmittance of the glass body for light having a wavelength of 420 to 800nm,

the difference between the wavelength of light having a transmittance of Tavg × 0.9 in the glass body and the wavelength of light having a transmittance of Tavg × 0.1 in the glass body is 20 to 50nm.

4. The glass laminate according to claim 3,

when Tavg is an average value of transmittances of the glass laminate with respect to light having a wavelength of 420 to 800nm,

the difference between the wavelength of light having a transmittance of Tavg × 0.9 in the glass laminate and the wavelength of light having a transmittance of Tavg × 0.1 in the glass laminate is 22nm or less.

5. The glass laminate according to any one of claims 1 to 4,

the glass laminate is characterized by being produced according to JIS T7330: the blue light reduction rate of 2000 is 35% or more.

6. The glass laminate according to any one of claims 1 to 5,

the glass body is characterized by being based on JIS K7373: the yellow index YI of 2006 is 5 or less.

7. The glass laminate according to any one of claims 1 to 6,

the glass laminate is characterized by being produced according to JIS K7373: the yellow index YI of 2006 is 10 or less.

8. The glass laminate according to any one of claims 1 to 7,

the glass laminate has a transmittance of 85% or less for light having a wavelength of 420 nm.

9. The glass laminate according to any one of claims 1 to 8,

is installed on the vehicle door as a lifting window.

10. The glass laminate according to any one of claims 1 to 8,

the glass is used as a windshield.

11. The glass laminate according to any one of claims 1 to 10,

the glass body has a first glass plate, a second glass plate, and an intermediate film disposed between the first glass plate and the second glass plate.

12. The glass laminate according to any one of claims 1 to 11,

the glass body further comprises a base sheet and an adhesive disposed between one of the glass plates and the base sheet and bonding the base sheet to the glass plate,

the ultraviolet blocking film is formed on the surface of the base sheet opposite to the adhesive.

13. The glass laminate according to any one of claims 1 to 12,

the thickness of the glass body is more than 2 mm.

14. The glass laminate according to any one of claims 1 to 13,

the glass body comprises at least 1 of the glass sheets having a surface compressive stress of less than 20MPa.

15. The glass laminate according to any one of claims 1 to 14,

at least 1 of the glass plates included in the glass body has a surface compressive stress of 80MPa or more.

16. The glass laminate according to any one of claims 1 to 14,

the glass body includes all the glass plates having a surface compressive stress of 80MPa or more.

17. The glass laminate according to any one of claims 1 to 16,

the surface of the glass laminate on which the ultraviolet ray blocking film is formed is subjected to a TABER abrasion test 1000 times under a 500g load in accordance with JIS R3221, and the glass laminate after the test has a haze ratio of 5% or less.

18. The glass laminate according to any one of claims 1 to 16,

irradiating the glass laminate with light having a wavelength of 295 to 450nm and an illuminance of 76mW/cm from a surface of the glass laminate opposite to the surface on which the ultraviolet blocking film is formed ² Is 100 hours, the difference between Tuv400 after the ultraviolet irradiation and Tuv400 before the ultraviolet irradiation is2% or less.

19. The glass laminate according to any one of claims 1 to 18,

the ultraviolet blocking film is removed in a region having a width of 20mm from the peripheral edge, the film thickness of the ultraviolet blocking film is thicker on the lower side of the vehicle than on the upper side of the vehicle, and the maximum value of the film thickness is 0.5 to 10 [ mu ] m.

20. The glass laminate according to any one of claims 1 to 19,

the ultraviolet barrier film has a film thickness in a region having a width of 20mm from the peripheral edge, wherein the position where the film thickness is the largest is 10cm or more from the peripheral edge of the film thickness, and the maximum value of the film thickness is 0.5 to 10 [ mu ] m.

21. The glass laminate according to claim 19 or 20,

the uniformity of the thickness of the ultraviolet barrier film is 70% or less.

22. The glass laminate according to any one of claims 1 to 21,

at least 1 of the glass plates included in the glass body contains a tin component on a first main surface and a second main surface of the glass plate, and the concentrations of the tin component contained in the first main surface and the second main surface are different.

23. The glass laminate according to any one of claims 1 to 22,

in the glass laminate, a mark is formed on a surface of the glass plate exposed to the outside,

the mark is constituted by a rough surface portion having a surface roughness Ra of 1.5 μm.

24. The glass laminate according to any one of claims 1 to 23,

the end face of the glass plate included in the glass body is formed in an arc shape protruding outward.

25. The glass laminate according to any one of claims 1 to 23,

the end faces of the glass plates included in the glass body are formed by connecting 3 or more flat faces,

the angle formed by the adjacent flat surfaces is an obtuse angle.

26. The glass laminate according to any one of claims 1 to 25,

the ultraviolet ray blocking film also has antifogging properties.

27. The glass laminate according to claim 26,

the ultraviolet ray blocking film also has water absorbing properties.

28. The glass laminate according to claim 26,

the surface of the ultraviolet ray blocking film is hydrophilic.

29. The glass laminate according to claim 26,

the ultraviolet blocking film also has a property of ensuring visibility.

30. The glass laminate according to claim 29,

the surface of the ultraviolet ray barrier film is water repellent.

31. The glass laminate according to any one of claims 1 to 25,

there is also a film to ensure visibility.

32. The glass laminate according to claim 31,

the visibility-securing film is disposed on a surface of the ultraviolet-ray blocking film opposite to the glass body side.

33. The glass laminate according to claim 31,

the glass body has a first glass plate, a second glass plate, and an intermediate film disposed between the first glass plate and the second glass plate,

the ultraviolet blocking film is disposed on at least one of the first glass plate and the second glass plate,

the visibility-securing film is disposed on the side of the first glass body and the second glass body opposite to the surface on which the ultraviolet blocking film is disposed.

34. The glass laminate according to any one of claims 1 to 33,

and also has a low reflection film.