WO2017183700A1

WO2017183700A1 - Windshield

Info

Publication number: WO2017183700A1
Application number: PCT/JP2017/015942
Authority: WO
Inventors: 大家　和晃; 洋平下川; 寺西　豊幸; 神谷　和孝
Original assignee: 日本板硝子株式会社
Priority date: 2016-04-22
Filing date: 2017-04-20
Publication date: 2017-10-26
Also published as: JPWO2017183700A1

Abstract

In order to prevent a reduction in the accuracy of information acquired by an information acquisition device, a windshield according to the present invention comprises a glass sheet, such as a laminated glass sheet 5, having on the vehicle interior surface thereof an antifogging film 8 containing a water repellent group and a metal-oxide composition. The surface of the glass sheet has an information acquisition region 12 which is disposed facing the information acquisition device 2 so as to allow light 22 travelling to the information acquisition device to pass therethrough. The antifogging film 8 is formed so as to cover at least the information acquisition region 12. The information acquisition region 12 may be isolated by a separation region 71, on which a blocking film 7 is formed, from a transparent region 11 providing the driver with a view of the outside. The antifogging film 8 may be formed so as not to cover the transparent region 11.

Description

Windshield

The present invention relates to a windshield suitable for use with an information acquisition device that receives light incident on the inside of a vehicle and acquires information outside the vehicle.

Vehicle collision avoidance systems that sense the distance to the vehicle ahead and automatically activate the brake when approaching abnormally are becoming widespread. This system acquires information such as the distance to the vehicle ahead and the presence of a pedestrian using an information acquisition device such as a camera or a radar using an infrared laser. Information acquisition devices are also required for automated driving devices that are being developed. Usually, an information acquisition device such as a camera is arranged close to the vehicle inner surface of the windshield, and receives light from outside the vehicle while irradiating light forward depending on the type of device, and Measure the distance of or detect the presence of pedestrians. Various types of windshields suitable for such a system have also been proposed. For example, Patent Document 1 discloses a laminated glass in which a translucent area is provided in a shade band coloring area.

JP 2006-96331 A

In low temperatures and cold areas, the accuracy of information acquired by the information acquisition device may be reduced, especially at the start of driving. This is a problem that occurs in common with information acquisition apparatuses that acquire information outside the vehicle by receiving light, such as a rain sensor, a light sensor, and an optical beacon, as well as a camera.

An object of the present invention is to provide a windshield suitable for preventing a decrease in accuracy of information acquired by an information acquisition device.

The present invention
A windshield suitable for arrangement of an information acquisition device that receives light incident from the outside of the vehicle into the vehicle and acquires information outside the vehicle,
A glass plate,
An antifogging film formed on the inner surface of the glass plate,
The antifogging film includes a water repellent group and a metal oxide component,
The surface on the inside of the vehicle has an information acquisition region through which the light incident on the information acquisition device is transmitted and the information acquisition device is arranged to face the surface.
The anti-fogging film provides a windshield formed so as to cover at least the information acquisition region.

The windshield according to the present invention is suitable for preventing a decrease in accuracy of information acquired by the information acquisition device.

In the windshield, the anti-fogging film has been formed exclusively to ensure the visibility of the driver and other passengers. Since the information acquisition area of the windshield is not an area for securing the field of view of the occupant, an antifogging film is essentially unnecessary. However, if an antifogging film is formed in this region, it is possible to prevent the straightness of light traveling to the information acquisition device from being impaired by water droplets generated by condensation of water vapor. In particular, an anti-fogging film containing a water-repellent group and a metal oxide component is unlikely to impair the straightness of light passing through the film even if water droplets are generated on the surface of the film, and the accuracy of information acquired by an information acquisition device Suitable for maintaining.

It is a top view which shows one Embodiment of the windshield which concerns on this invention by the state which looked at the said windshield from the vehicle inside. It is a fragmentary sectional view of FIG. It is a fragmentary sectional view which shows another embodiment of the windshield which concerns on this invention. It is a top view which shows another embodiment of the windshield which concerns on this invention. It is a fragmentary sectional view which shows another embodiment of the windshield which concerns on this invention. It is a fragmentary sectional view which shows another embodiment of the windshield which concerns on this invention. It is a fragmentary sectional view of the windshield for showing an example of the film thickness distribution of an anti-fogging film. It is a fragmentary sectional view of the windshield for showing another example of the film thickness distribution of an anti-fogging film. It is a schematic diagram which shows the state which water vapor | steam condensed on the surface of the anti-fogging film | membrane with a relatively large contact angle of water. It is a schematic diagram which shows the state which water vapor | steam condensed on the surface of the anti-fogging film | membrane with a relatively small contact angle of water.

Hereinafter, details of the present invention will be described, but the following description is not intended to limit the present invention to a specific embodiment. In this specification, the term “water-repellent group” means a linear or cyclic alkyl group having 1 to 30 carbon atoms in which at least part of hydrogen atoms may be substituted with fluorine atoms. The term “metal oxide component” is intended to include a component consisting of only metal atoms and oxygen atoms bonded to each other, as well as a portion where metal atoms and oxygen atoms are directly bonded. Therefore, for example, the portion represented by MO in the component represented by the formula RMO (R: water repellent group, M: metal atom) constitutes a metal oxide component. Further, the term “metal” in the terms “metal oxide component”, “metal atom”, “metal compound” and the like is used in a sense including boron (B) and silicon (Si) according to common usage.

As shown in FIGS. 1 and 2, the windshield 1 according to the present embodiment includes a laminated glass 5 as a glass plate that defines a vehicle interior space and a vehicle exterior space in front of the vehicle body. The laminated glass 5 is installed on the vehicle body in an inclined state so that the outer surface of the vehicle faces obliquely upward. In a part of the region including the peripheral edge of the laminated glass 5, a shielding film 7 formed in the part of the region is provided so that the region is opaque. In the illustrated form, the shielding film 7 is formed on the inner surface of the laminated glass 5, but may be formed on another surface, for example, the inner surface of the outer glass plate 53. In a typical form, the inner surface of the vehicle is a concave surface of laminated glass.

The information acquisition device 2 includes a light receiving unit 21 and is disposed in proximity to the laminated glass 5 so that the light receiving unit 21 can receive light transmitted through the laminated glass 5. The information acquisition device 2 is, for example, a photographing device such as a video camera for photographing a situation outside the vehicle, or a laser radar that emits a laser beam and receives a laser beam reflected by an object outside the vehicle. The information acquisition device 2 may be a rain sensor, a light sensor, an optical beacon, or the like. The information acquisition device 2 is connected to the information processing device 3 that processes the acquired information.

The vehicle inner surface of the windshield 1 shown in FIG. 1 covered with the shielding film 7 has a peripheral region 70 and a separation region 71 that are not seen through. The peripheral region 70 is disposed along the peripheral edge of the laminated glass 5 so as to surround the see-through region 11 spreading in the center of the laminated glass 5. The see-through region 11 is a region in which the see-through property is ensured so that the driver and other occupants can visually recognize the outside of the vehicle. Both ends of the separation region 71 are connected to the peripheral region 70 so that an opening 72 is formed between the separation region 71 and the peripheral region 70. In the opening 72, similarly to the perspective region 11, light from the outside of the vehicle can be transmitted into the vehicle. The information acquisition region 12 through which the light 22 incident on the information acquisition device 2 passes is located in the opening 72. The transparent region 11 and the information acquisition region 12 are separated by a separation region 71 that is a shielding region on which the shielding film 7 is formed.

Unlike the embodiment shown in FIG. 1, the separation region 71 may be arranged so as to be separated from the peripheral region 70 and so that the opening 72 is surrounded only by the separation region 71. Further, the shielding film 7 is not limited to the form shown in FIG. 1, and the shielding film 7 may be formed so that at least a part of the shielding area where the shielding film 7 is formed is disposed between the fluoroscopic area 11 and the information acquisition area 12. . The shielding film 7 may be formed on a surface other than the vehicle inner surface of the laminated glass 5, for example, the vehicle outer surface of the inner glass plate 51 or the vehicle inner surface of the outer glass plate 53.

The information acquisition region 12 is defined as a range through which light 22 that can be received by the light receiving unit 21 of the information acquisition device 2 is transmitted. In the form shown in FIGS. 1 and 2, the opening 72 provided in the shielding film 7 is set wider than the information acquisition region 12. However, the present invention is not limited to this, and as shown in FIG. 3, the opening 72 and the information acquisition region 12 may substantially coincide with each other.

The laminated glass 5 may have two or more information acquisition regions 12. In the form shown in FIG. 4, two

information acquisition regions

12 and 12 are formed on the laminated glass 5, which are separated from each other and from the perspective region 11 by the separation region 71. Each has an information acquisition device. As shown in FIGS. 1 and 4, the information acquisition area 12 is often provided near the upper side of the windshield 1, but the position of the area 12 is not limited to this.

An antifogging film 8 is formed on the inner surface of the laminated glass 5 so as to cover at least the information acquisition region 12. The antifogging film 8 may be a multilayer film, but is preferably a single layer film. The antifogging film 8 is directly formed on the surface of the laminated glass 5 which is a glass plate constituting a windshield. In the embodiment described above, the antifogging film 8 is formed so as to cover the information acquisition region 12 but not the transparent region 11.

The water vapor in the car is consumed by forming water droplets at the site where it condenses easily. Therefore, from the viewpoint of preventing the formation of water droplets in the information acquisition region 12, the antifogging film 8 is formed in the fluoroscopic region 11 rather than the form in which the antifogging film 8 is disposed in the fluoroscopic region 11 together with the information acquisition region 12. The non-formal form is advantageous. That is, in the form in which the antifogging film 8 is formed so as to avoid the see-through region 11, the water vapor in the vehicle escapes from the supersaturated state by being consumed as water droplets in the see-through region 11 where the glass surface is exposed. No. 12 makes it difficult for water vapor to condense. Water droplets generated on the fluoroscopic region 11 can be removed by, for example, warm air blown from a defroster below the windshield at the start of operation. The cloudiness caused by water droplets on the fluoroscopic region 11 is far easier to detect than the cloudiness of the information acquisition region 12 in which the information acquisition device 2 is installed in the vicinity (which makes driving difficult in some cases). There is no difficulty for the person to start the removal operation.

It is known that the antifogging film 8 formed on the shielding film 7 is easily peeled off. For this reason, when forming the anti-fogging film 8 in the see-through region 11, it is customary to apply the working solution of the anti-fogging film 8 only to the central part avoiding the peripheral part where the shielding film 7 is formed. . From such a conventional method, the antifogging film 8 is formed so as to cover the fluoroscopic region 11 but not the information acquisition region 12 in the opening 72, contrary to the form shown in FIGS. 2 and 3. A windshield will be obtained. This form is effective in reducing the frequency of the operation for removing the fogging of the fluoroscopic region 11. However, the operation is started in a state where water droplets are left in the information acquisition region 12, and it is easy to cause a result that information with low accuracy is acquired from light scattered when passing through the water droplets.

However, the present invention is not limited thereto, and the antifogging film 8 may be formed so as to cover at least a part of the fluoroscopic region 11 together with the information acquisition region 12. The antifogging film 8 may be formed, for example, separately into a first part 81 in the opening 72 of the shielding film 7 and a second part 82 covering at least a part of the transparent region 11 (FIG. 5). You may form in the vehicle interior surface whole region including the area |

regions

70 and 71 in which the shielding film 7 was formed, and the area |

regions

11 and 72 which can be seen through (FIG. 6). Although not shown, the antifogging film 8 may be formed in the remaining

regions

11, 71, 72 on the vehicle inner surface excluding the peripheral region 70. As is well known, the formation of the antifogging film 8 only in a desired region can be carried out, for example, by masking the region other than the region and applying the working solution of the antifogging film 8.

As shown in FIG. 7A and FIG. 7B, the film thickness of the antifogging film 8 is not constant but may be gradually changed. As shown in FIG. 7A, the antifogging film 8 has a film thickness at the lower end 12a of the information acquisition region 12 that is greater than the film thickness at the upper end 12b of the information acquisition region 12 when the windshield 1 is installed on the vehicle body. May have a large film thickness distribution. The thicker the film thickness, the higher the antifogging property, and the information acquired by the information acquisition device 2 has a lot of important information distributed below the horizontal line of the position of the information acquisition device 2. However, the accuracy of information acquired by the information acquisition device 2 is unlikely to decrease. The ratio of the film thickness at the lower end portion 12a to the film thickness at the upper end portion 12b is preferably 1.1 or more and 3 or less, and more preferably 1.2 or more and 2.5 or less. However, the film thickness distribution of the antifogging film 8 is not limited to the above, and as shown in FIG. 7B, the film thickness distribution at the upper end portion 12b is larger than the film thickness at the lower end portion 12a. It may be. Since the windshield begins to cloud first from the periphery thereof, when the upper part is thick, a part of the information acquisition region 12 can be prevented from clouding first. A preferable ratio of the film thickness at the upper end 12b to the film thickness at the lower end 12a is the same as the above-described range described in the case where the magnitude relationship of the film thickness is opposite.

<Members constituting laminated glass>
Hereinafter, the member which comprises a common laminated glass as a glass plate which comprises a windshield is demonstrated. The laminated glass 5 generally includes an inner glass plate 51 and an outer glass plate 53, and the

glass plates

51 and 53 are bonded to each other by a resin intermediate film 52 disposed therebetween. The

glass plates

51 and 53 may be known glass plates, for example, glass plates called clear glass, green glass, UV green glass and the like. However, it is necessary to select the composition of the

glass plates

51 and 53 so that the visible light transmittance of the laminated glass 5 satisfies the standard of the country in which the laminated glass 5 is used (for example, 70% or more, or 75% or more). .

The thickness of the laminated glass 5 is not particularly limited, but the total thickness of the outer glass plate 53 and the inner glass plate 51 may be 2.1 to 6 mm, for example, and 2.4 from the viewpoint of weight reduction. 3.8 mm, more preferably 2.6 to 3.4 mm, and particularly preferably 2.7 to 3.2 mm. The thickness of the outer glass plate 53 may be larger than that of the inner glass plate 51 in order to ensure durability against external obstacles and impact resistance, for example, 1.8 to 2.3 mm, and further 1.9 to 2.1 mm is preferred. The thickness of the inner glass plate 51 may be the same as that of the outer glass plate 53, but may be smaller than the outer glass plate 53 in order to reduce the weight of the laminated glass 5, for example, 0.6 to 2.0 mm. Further, it is preferably 0.8 to 1.6 mm, particularly preferably 1.0 to 1.4 mm, particularly preferably 1.0 to 1.3 mm.

The intermediate film 53 can be formed of a known resin, for example, a polyvinyl butyral resin or an ethylene-vinyl acetate copolymer resin. The intermediate film 53 may be a single layer film or a multilayer film. An example of the multilayer film is a film having a three-layer structure in which a soft core layer is sandwiched from both sides by an outer layer harder than the core layer.

If necessary, functional fine particles may be dispersed in the intermediate film 53. As functional fine particles, fine particles of various oxides, nitrides, metals, and organic compounds can be used. Preferred functional fine particles include ATO (conductive antimony-containing tin oxide) and ITO (conductive tin-containing indium oxide). The particle diameter of the functional fine particles is not particularly limited, but is preferably 0.2 μm or less, for example, 0.001 to 0.15 μm.

<Shielding layer>
Next, the shielding film 7 will be described. The shielding film 7 is often called a ceramic print and functions as a mask that blocks the line of sight from the outside of the vehicle. The shielding film 7 can be formed by printing a ceramic paste in a predetermined pattern and firing the printed ceramic paste. The ceramic paste has, for example, a black pigment, a glass frit for heat-bonding with a glass plate to express mechanical strength, an organic binder that can be removed by firing, and a viscosity suitable for screen printing. It is a mixture with organic solvents such as pine oil.

The firing of the ceramic paste can be simultaneously performed by heating at the time of bending the

glass plates

51 and 53.

<Anti-fogging film>
Next, the antifogging film 8 will be described. The antifogging film 8 includes a water repellent group and a metal oxide component, and preferably further includes a water absorbent resin. The antifogging film 8 may further contain other functional components as necessary. The type of water-absorbing resin is not limited as long as it can absorb and retain water. The water repellent group can be supplied to the antifogging film from a metal compound having a water repellent group (water repellent group-containing metal compound). The metal oxide component can be supplied to the antifogging film 8 from a water repellent group-containing metal compound, other metal compounds, metal oxide fine particles and the like. Hereinafter, each component will be described.

(Water absorbent resin)
Examples of the water absorbent resin include at least one selected from the group consisting of urethane resin, epoxy resin, acrylic resin, polyvinyl acetal resin, and polyvinyl alcohol resin. Examples of the urethane resin include a polyurethane resin composed of a polyisocyanate and a polyol. As the polyol, an acrylic polyol and a polyoxyalkylene polyol are preferable. Examples of the epoxy resins include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and cyclic aliphatic epoxy resins. A preferred epoxy resin is a cycloaliphatic epoxy resin. Hereinafter, the polyvinyl acetal resin which is a preferable water-absorbent resin will be described.

Polyvinyl acetal can be obtained by subjecting polyvinyl alcohol to an acetal reaction by condensation reaction of aldehyde with polyvinyl alcohol. The acetalization of polyvinyl alcohol may be carried out using 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 saponification of polyvinyl acetate. The degree of acetalization is preferably 2 to 40 mol%, more preferably 3 to 30 mol%, particularly 5 to 20 mol%, and in some cases 5 to 15 mol%. The degree of acetalization can be measured based on, for example, ¹³ C nuclear magnetic resonance spectroscopy. Polyvinyl acetal having an acetalization degree in the above range is suitable for forming an antifogging film having good water absorption and water resistance.

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

Examples of the aldehyde to be subjected to a condensation reaction with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexyl carbaldehyde, octyl carbaldehyde, decyl carbaldehyde. In addition, benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl group-substituted benzaldehydes; chlorobenzaldehyde, other halogen atom-substituted benzaldehydes; alkyl such as hydroxy group, alkoxy group, amino group, cyano group Examples thereof include substituted benzaldehydes in which a hydrogen atom is substituted by a functional group excluding a group; aromatic aldehydes such as condensed aromatic aldehydes such as naphthaldehyde and anthraldehyde. Aromatic aldehydes with strong hydrophobicity are advantageous in forming an antifogging film having a low degree of acetalization and excellent water resistance. The use of an aromatic aldehyde is also advantageous in forming a film having high water absorption while leaving many hydroxyl groups remaining. The polyvinyl acetal preferably contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

The content of the water-absorbing resin in the anti-fogging film is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% by mass or more, from the viewpoints of film hardness, water absorption and anti-fogging property. It is 95 mass% or less, More preferably, it is 90 mass% or less, Most preferably, it is 85 mass% or less.

(Water repellent group)
The water-repellent group facilitates the balance between the strength and anti-fogging property of the anti-fogging film and contributes to ensuring the straightness of incident light even if water droplets are formed by making the surface of the film hydrophobic. . In order to sufficiently obtain the effect of the water repellent group, it is preferable to use a water repellent group having high water repellency. Preferred water repellent groups are (1) a chain or cyclic alkyl group having 3 to 30 carbon atoms, and (2) a chain or cyclic group having 1 to 30 carbon atoms in which at least a part of hydrogen atoms are substituted with fluorine atoms. It is at least one selected from alkyl groups (hereinafter sometimes referred to as “fluorine-substituted alkyl groups”).

Regarding (1) and (2), the chain or cyclic alkyl group is preferably a chain alkyl group. The chain alkyl group may be a branched alkyl group, but is preferably a linear alkyl group. An alkyl group having more than 30 carbon atoms may cause the antifogging film to become cloudy. From the viewpoint of the balance between the antifogging property, strength and appearance of the film, the chain alkyl group preferably has 20 or less carbon atoms, for example, 1 to 8, for example 4 to 16, preferably 4 to 8. is there. Particularly preferred alkyl groups are linear alkyl groups having 4 to 8 carbon atoms, such as n-pentyl, n-hexyl, n-heptyl, and n-octyl. Regarding (2), the fluorine-substituted alkyl group may be a group in which only part of the hydrogen atoms of the chain or cyclic alkyl group is substituted with fluorine atoms, and all of the hydrogen atoms of the chain or cyclic alkyl group. May be a group substituted with a fluorine atom, for example, a linear perfluoroalkyl group. Since the fluorine-substituted alkyl group has high water repellency, a sufficient effect can be obtained by adding a small amount. However, if the content of the fluorine-substituted alkyl group is too large, it may be separated from other components in the coating solution for forming a film.

(Hydrolyzable metal compound having water repellent group)
In order to add a water repellent group to the antifogging film, 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 hydrolyzable functional group or a halogen atom ( A water repellent group-containing hydrolyzable metal compound) or a hydrolyzate thereof may be added to a coating solution for forming a film. In other words, the water repellent group may be derived from a water repellent group-containing hydrolyzable metal compound. 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)
Here, R is a water repellent group, that is, a linear or cyclic alkyl group having 1 to 30 carbon atoms in which at least part of hydrogen atoms may be substituted with fluorine atoms, and Y is a hydrolyzable functional group. A group or a halogen atom, and m is an integer of 1 to 3. The hydrolyzable functional group is, for example, at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, and an amino group, preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. An alkenyloxy group is, for example, an isopropenoxy group. The halogen atom is preferably chlorine. The functional groups exemplified here can also be used as “hydrolyzable functional groups” described below. m is preferably 1 or 2.

The compound represented by formula (I) supplies the component represented by the following formula (II) when hydrolysis and polycondensation have completely proceeded.
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 bonded to each other through oxygen atoms in the antifogging film.

As described above, the compound represented by the formula (I) is hydrolyzed or partially hydrolyzed, and further, at least partly polycondensed to alternately connect silicon atoms and oxygen atoms, and three-dimensionally. A network structure of spreading siloxane bonds (Si—O—Si) is formed. A water repellent group R is connected to silicon atoms included in the network structure. In other words, the water repellent group R is fixed to the network structure of the siloxane bond through the bond R—Si. This structure is advantageous in uniformly dispersing the water repellent group R in the film. The network structure may contain a silica component supplied from a silicon compound (for example, tetraalkoxysilane, silane coupling agent) other than the water repellent group-containing hydrolyzable silicon compound represented by the formula (I). In order to form an antifogging film together with a hydrolyzable silicon compound having no water repellent group and a hydrolyzable functional group or halogen atom (water repellent group-free hydrolyzable silicon compound) together with a water repellent group-containing hydrolyzable silicon compound In this coating solution, a network structure of siloxane bonds including silicon atoms bonded to water repellent groups and silicon atoms not bonded to water repellent groups can be formed. With such a structure, it becomes easy to adjust the water repellent group content and the metal oxide component content in the antifogging film independently of each other.

When the anti-fogging film contains a water-absorbing resin, the water-repellent group improves the anti-fogging performance by improving the water vapor permeability on the surface of the anti-fogging film containing the water-absorbing resin. Since the two functions of water absorption and water repellency are contradictory to each other, the water-absorbing material and the water-repellent material have been conventionally distributed and assigned to different layers. The uneven distribution of water in the vicinity of the surface of the cloud layer is eliminated, the time until condensation is extended, and the anti-fogging property of the anti-fogging film is improved. The effect will be described below.

Water vapor that has entered the anti-fogging film containing the water-absorbing resin is hydrogen-bonded with a hydroxyl group of the water-absorbing resin or the like, and is retained in the form of bound water. As the amount increases, the water vapor is retained from the bound water form to the semi-bound water form and finally to the free water form retained in the voids in the antifogging membrane. In the antifogging film, the water repellent group prevents the formation of hydrogen bonds and facilitates the dissociation of the formed hydrogen bonds. If the content of the water-absorbing resin is the same, there is no difference in the number of hydroxyl groups capable of hydrogen bonding in the film, but the water-repellent group reduces the rate of hydrogen bond formation. Therefore, in the anti-fogging film containing a water repellent group, moisture is finally retained in the film in any of the above forms, but by the time it is retained, it remains as water vapor up to the bottom of the film. Can diffuse. Also, the water once retained is easily dissociated and easily moves to the bottom of the membrane in the state of water vapor. As a result, the distribution of moisture retention in the film thickness direction is relatively uniform from the vicinity of the surface to the bottom of the film. That is, since all of the thickness direction of the anti-fogging film can be effectively utilized and water supplied to the film surface can be absorbed, water droplets hardly condense on the surface and the anti-fogging property is improved.

On the other hand, in a conventional antifogging film that does not contain a water repellent group, water vapor that has entered the film is very easily retained in the form of bound water, semi-bonded water, or free water. Therefore, the invading water vapor tends to be held near the surface of the film. As a result, the moisture in the film is extremely near the surface and decreases rapidly as it goes to the bottom of the film. That is, although the water can still be absorbed at the bottom of the film, it is saturated with water near the surface of the film and condensed as water droplets, so that the antifogging property is limited.

When a water-repellent group is introduced into an antifogging film 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 this network structure is advantageous not only from the viewpoint of wear resistance but also from the viewpoint of improving hardness, water resistance and the like.

The water repellent group may be added to such an extent that the contact angle of water on the surface of the antifogging film is 70 degrees or more, preferably 80 degrees or more, more preferably 90 degrees or more. For the contact angle of water, a value measured by dropping a 4 mg water droplet on the surface of the membrane is adopted. In particular, when a methyl group or an ethyl group having a slightly weak water repellency is used as the water repellent group, it is preferable to add an amount of the water repellent group having a water contact angle in the above range to the antifogging film. The upper limit of the contact angle of water is not particularly limited, but is, for example, 150 degrees or less, 120 degrees or less, and 105 degrees or less. It is preferable that the water repellent group is uniformly contained in the antifogging film so that the contact angle of water is in the above range in all regions on the surface of the antifogging film.

As shown in FIGS. 8 and 9, the area of

water droplets

80 and 81 formed by condensation of the same amount of water vapor on the surface of the antifogging film 8 covers the antifogging film 8 is determined by the contact angle of water on the surface. There is a tendency to decrease as the value increases. The smaller the area covered by the

water droplets

80 and 81, the smaller the ratio of the area where the light incident on the antifogging film 8 is scattered. Therefore, the anti-fogging film 8 having a water contact angle increased due to the presence of the water repellent group is advantageous in maintaining the straightness of transmitted light in a state where water droplets are formed on the surface thereof.

The antifogging film preferably contains a water-repellent group so that the contact angle of water is in the above-mentioned preferable range. When the water-absorbing resin is included, the anti-fogging film is 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the water-absorbing resin. In addition, it is preferable that a water-repellent group is included so as to be within a range of 10 parts by mass or less, preferably 5 parts by mass or less.

(Metal oxide component)
The antifogging film contains a metal oxide component. The metal oxide component is, for example, an oxide component of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, and preferably an Si oxide component (silica component) ). When the water-absorbing resin is included, the anti-fogging film is 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 100 parts by mass of the water-absorbing resin. 1 part by mass or more, particularly preferably 5 parts by mass or more, in some cases 7 parts by mass or more, if necessary 10 parts by mass or more, 60 parts by mass or less, particularly 50 parts by mass or less, preferably 40 parts by mass or less, More preferably, the metal oxide component is contained so as to be 30 parts by mass or less, particularly preferably 20 parts by mass or less, and in some cases 18 parts by mass or less. The metal oxide component is a component necessary for ensuring the strength of the film, particularly the scratch resistance. However, if its content is excessive, the antifogging property of the film is lowered.

At least a part of the metal oxide component may be a hydrolyzable metal compound or a metal oxide component derived from the hydrolyzate added to a coating solution for forming an antifogging film. Here, the hydrolyzable metal compound has a) a metal compound having a water repellent group and a hydrolyzable functional group or a halogen atom (water repellent group-containing hydrolyzable metal compound), and b) a water repellent group. It is at least one selected from a metal compound having a hydrolyzable functional group or a halogen atom (a water-repellent group-free hydrolyzable metal compound). The metal oxide component derived from a) and / or b) is an oxide of metal atoms constituting the hydrolyzable metal compound. The metal oxide component includes the metal oxide component derived from the metal oxide fine particles added to the coating solution for forming the antifogging film, the hydrolyzable metal compound added to the coating solution, or the And a metal oxide component derived from the hydrolyzate. Again, the hydrolyzable metal compound is at least one selected from a) and b) above. The b), that is, the hydrolyzable metal compound having no water repellent group may contain at least one selected from tetraalkoxysilane and a silane coupling agent. Hereinafter, the metal oxide fine particles and the above b) will be described except for the above-described a).

(Metal oxide fine particles)
The antifogging film 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 one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, preferably silica fine particles. is there. Silica fine particles can be introduced into the film, for example, by adding colloidal silica. The metal oxide fine particles are excellent in the action of transmitting the stress applied to the antifogging film to the transparent article supporting the film, and have a high hardness. Therefore, the addition of metal oxide fine particles is advantageous from the viewpoint of improving the wear resistance and scratch resistance of the antifogging film. In addition, when metal oxide fine particles are added to the antifogging film, fine voids are formed at sites where the fine particles are in contact with or close to, and water vapor is easily taken into the film from the voids. For this reason, the addition of metal oxide fine particles may advantageously work to improve antifogging properties. The metal oxide fine particles can be supplied to the antifogging film by adding metal oxide fine particles formed in advance to a coating solution for forming the antifogging film.

If the average particle size of the metal oxide fine particles is too large, the film may become cloudy. If the average particle size is too small, it is difficult to agglomerate and disperse uniformly. From this viewpoint, the preferable average particle diameter of the metal oxide fine particles is 1 to 20 nm, particularly 5 to 20 nm. Here, the average particle diameter of the metal oxide fine particles is described in the state of primary particles. In addition, the average particle diameter of the metal oxide fine particles is determined by measuring the particle diameters of 50 fine particles arbitrarily selected by observation using a scanning electron microscope and adopting the average value. If the content of the metal oxide fine particles is excessive, the water absorption amount of the entire film is lowered and the film may become cloudy. When the antifogging film contains a water absorbent resin, the metal oxide fine particles are 0 to 50 parts by weight, preferably 1 to 30 parts by weight, more preferably 2 to 30 parts by weight, particularly 100 parts by weight of the water absorbent resin. Preferably, it is added in an amount of 5 to 25 parts by mass, and in some cases 10 to 20 parts by mass.

(Hydrolyzable metal compound having no water repellent group)
The anti-fogging film may contain a metal oxide component derived from a hydrolyzable metal compound having no water-repellent group (water-repellent group-free hydrolyzable compound). A preferred hydrolyzable metal compound containing no water repellent group is a hydrolyzable silicon compound having no water repellent group. The hydrolyzable silicon compound having no water repellent group is, for example, at least one silicon compound selected from silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane and aminosilane (however, having no water repellent group), Silicon alkoxide having no water repellent group is preferred. An example of alkenyloxysilane is isopropenoxysilane.

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 one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, an amino group, and a halogen atom.

The water repellent group-free hydrolyzable metal compound is hydrolyzed or partially hydrolyzed, and further, at least a part thereof is polycondensed to supply a metal oxide component in which a metal atom and an oxygen atom are bonded. This component can strongly bond the metal oxide fine particles and the water-absorbent resin, and can contribute to improvement of the wear resistance, hardness, water resistance, etc. of the antifogging film. When the antifogging film contains a water-absorbing resin, the metal oxide component derived from the hydrolyzable metal compound having no water-repellent group is 0 to 40 parts by mass, preferably 0. The amount may be in the range of 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, particularly preferably 3 to 10 parts by mass, and in some cases 4 to 12 parts by mass.

A preferred 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. Tetraalkoxysilanes include, for example, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, and tetra-tert- It is at least one selected from butoxysilane.

When the content of the metal oxide (silica) component derived from tetraalkoxysilane is excessive, the antifogging property of the antifogging film may be lowered. One reason is that the softness of the antifogging film is reduced and the swelling and shrinkage of the film accompanying the absorption and release of moisture is limited. When the antifogging film contains a water-absorbing resin, the metal oxide component derived from tetraalkoxysilane is 0 to 30 parts by weight, preferably 1 to 20 parts by weight, more preferably 3 parts per 100 parts by weight of the water-absorbing resin. It may be added in a range of ˜10 parts by mass.

Another preferred example of the hydrolyzable silicon compound having no water repellent group is a silane coupling agent. Silane coupling agents are silicon compounds having different reactive functional groups. A part of the reactive functional group is preferably a hydrolyzable functional group. The silane coupling agent is, for example, a silicon compound having an epoxy group and / or an amino group and a hydrolyzable functional group. Examples of preferable silane coupling agents include glycidyloxyalkyltrialkoxysilane and aminoalkyltrialkoxysilane. In these silane coupling agents, the number of carbon atoms of the alkylene group directly bonded to the silicon atom is preferably 1 to 3. Since the glycidyloxyalkyl group and the aminoalkyl group include a functional group (epoxy group or amino group) that exhibits hydrophilicity, the glycidyloxyalkyl group and the aminoalkyl group are not water-repellent as a whole although they include an alkylene group.

The silane coupling agent strongly binds the water-absorbing resin that is an organic component and the metal oxide fine particles that are an inorganic component, and can contribute to the improvement of wear resistance, hardness, water resistance, and the like of the antifogging film. However, when the content of the metal oxide (silica) component derived from the silane coupling agent is excessive, the antifogging property of the antifogging film is lowered, and in some cases, the antifogging film becomes cloudy. When the antifogging film contains a water-absorbing resin, the metal oxide component derived from the silane coupling agent is 0 to 10 parts by weight, preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the water-absorbing resin. Preferably, it is added in the range of 0.1 to 2 parts by mass.

(Crosslinked structure)
The antifogging film may include a crosslinked structure derived from a crosslinking agent, preferably at least one crosslinking agent selected from an organic boron compound, an organic titanium compound, and an organic zirconium compound. The introduction of a crosslinked structure improves the wear resistance, scratch resistance and water resistance of the antifogging film. From another viewpoint, the introduction of a crosslinked structure facilitates improving the durability of the antifogging film without deteriorating the antifogging performance.

When a crosslinked structure derived from a crosslinking agent is introduced into the antifogging film in which the metal oxide component is a silica component, the antifogging film has a metal atom other than silicon as a metal atom, preferably boron, titanium or zirconium, May be contained.

The type of the crosslinking agent is not particularly limited as long as it can crosslink the water-absorbing resin to be used. Here, an example is given only for the organic titanium compound. The organic titanium compound is, for example, at least one selected from titanium alkoxide, titanium chelate compound, and titanium acylate. The titanium alkoxide is, for example, titanium tetraisopropoxide, titanium tetra-n-butoxide, or titanium tetraoctoxide. 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 lactate ammonium). The titanium acylate is, for example, titanium stearate. Preferred organic titanium compounds are titanium chelate compounds, particularly titanium lactate.

When the water-absorbing resin is polyvinyl acetal, a preferable cross-linking agent is an organic titanium compound, particularly titanium lactate.

(Other optional ingredients)
You may mix | blend another additive with an anti-fogging film | membrane. Examples of the additive include glycols such as glycerin and ethylene glycol having a function of improving antifogging properties. Additives may be surfactants, leveling agents, ultraviolet absorbers, colorants, antifoaming agents, preservatives, and the like.

(Film thickness)
What is necessary is just to adjust the film thickness of the anti-fogging film 8 suitably according to the anti-fogging characteristic etc. which are requested | required. The preferred film thickness of the antifogging film 8 is 1 to 20 μm, preferably 2 to 15 μm, particularly 3 to 10 μm.

(Film formation)
The antifogging film 8 is formed by applying a coating liquid for forming the antifogging film 8 onto a transparent article such as a transparent substrate, drying the applied coating liquid, and further performing a high temperature and high humidity treatment as necessary. By carrying out, a film can be formed. Conventionally known materials and methods may be used as the solvent used for preparing the coating liquid and the coating method.

In the coating liquid coating step, it is preferable to maintain the relative humidity of the atmosphere at less than 40%, more preferably 30% or less. Keeping the relative humidity low can prevent the film from absorbing excessive moisture from the atmosphere. If a large amount of moisture is absorbed from the atmosphere, the water remaining in the membrane matrix may reduce the strength of the membrane.

It is preferable that the drying process of the coating liquid includes an air drying process and a heating drying process with heating. The air drying step is preferably performed by exposing the coating liquid to an atmosphere in which the relative humidity is kept below 40%, and further 30% or less. The air drying process can be performed as a non-heating process, in other words, at room temperature. When a hydrolyzable silicon compound is contained in the coating liquid, in the heat drying step, a dehydration reaction involving a silanol group contained in the hydrolyzate of the silicon compound and a hydroxyl group present on the transparent article proceeds, A matrix structure (Si—O bond network) composed of silicon atoms and oxygen atoms develops.

In order to avoid decomposition of organic substances such as water-absorbing resin, the temperature applied in the heat drying process should not be excessively high. An appropriate heating temperature in this case is 300 ° C. or less, for example, 100 to 200 ° C., and the heating time is 1 minute to 1 hour.

When forming the antifogging film 8, a high temperature and high humidity treatment step may be appropriately performed. By carrying out the high-temperature and high-humidity treatment step, it is possible to more easily balance the antifogging property and the strength of the film. The high-temperature and high-humidity treatment step can be carried out, for example, by holding in an atmosphere of 50 to 100 ° C. and a relative humidity of 60 to 95% for 5 minutes to 1 hour. The high temperature and high humidity treatment step may be performed after the coating step and the drying step, or may be performed after the coating step and the air drying step and before the heat drying step. Particularly in the former case, a heat treatment step may be further performed after the high temperature and high humidity treatment step. This additional heat treatment step can be performed, for example, by holding in an atmosphere of 80 to 180 ° C. for 5 minutes to 1 hour.

Further, the antifogging film 8 formed from the coating liquid may be washed and / or wiped with a poultice as necessary. Specifically, it can be carried out by exposing the surface of the anti-fogging film 8 to a water flow or wiping with a cloth soaked with water. The water used in these is suitably pure water. It is better to avoid using solutions containing detergents for cleaning. By this step, dust, dirt, etc. adhering to the surface of the antifogging film 8 can be removed, and a clean coating surface can be obtained.

As is clear from the above description, examples of the preferred form of the antifogging film include the following.
i) An antifogging film comprising 0.1 to 60 parts by mass of a metal oxide component and 0.05 to 10 parts by mass of a water-repellent group with respect to 100 parts by mass of the water-absorbing resin.
ii) The water repellent group is a chain alkyl group having 1 to 8 carbon atoms, and the water repellent group is directly bonded to the metal atom constituting the metal oxide component, and the metal atom is silicon, and is antifogging. film.
iii) A metal oxide component derived from a hydrolyzable metal compound or a hydrolyzate of a hydrolyzable metal compound, wherein at least a part of the metal oxide component is added to a coating solution for forming an antifogging film. The anti-fogging film, wherein the hydrolyzable metal compound is at least one selected from a hydrolyzable metal compound having a water repellent group and a hydrolyzable metal compound having no water repellent group.
iv) The antifogging film according to iii), wherein the hydrolyzable metal compound having no water repellent group contains at least one selected from tetraalkoxysilane and silane coupling agent.

The following are examples in which various properties of the antifogging film formed on the glass plate were confirmed. First, a method for evaluating the characteristics of the samples produced in the examples will be described.

(1) Appearance The transparency of the sample and the presence or absence of cracks were visually observed and evaluated according to the following criteria.
○: Good Δ: Slight cloudiness is observed.
X: Unevenness, white turbidity, cracks, etc. are observed in the film, and there are practical problems.

(2) Film thickness The sample was allowed to stand in an environment of room temperature 20 ° C. and relative humidity 50% for 1 hour, and then the film thickness of the antifogging film was measured using a surface shape measuring instrument α-Step 500 manufactured by KLA Tencor. .

(3) Contact angle After leaving the sample in an environment of room temperature 20 ° C. and relative humidity 50% for 1 hour, using a contact angle meter (CA-A) manufactured by Kyowa Interface Science Co., Ltd., about 4 μL (= 4 mg) A water droplet was dropped on the surface of the antifogging film, and the contact angle of the water droplet on the surface of the antifogging film was measured.

(4) Anti-fogging property The sample was allowed to stand for 1 hour in an environment of room temperature 20 ° C. and relative humidity 30%. On the other hand, warm water whose water temperature is kept at 40 ° C. is stored in a constant temperature water tank, and the sample is placed above the warm water so that the antifogging film is exposed to water vapor, and the time until cloudiness is recognized in the antifogging film is set. It was measured. In addition, in the glass plate (soda lime glass plate) which has not provided the anti-fogging film | membrane, fogging was confirmed in 10 seconds or less. The time until cloudiness was formed was evaluated according to the following criteria.
A: Clouding was confirmed after 85 seconds.
○: Clouding was confirmed over 60 seconds and 85 seconds or less.
(Triangle | delta): Cloudiness was confirmed in 30 seconds or more and 60 seconds or less.
X: Cloudiness was confirmed in 30 seconds or less.

(5) Dry cloth wiping resistance A nell cloth (No. 300) is attached to a reciprocating abrasion tester (“HEIDON-18” manufactured by Shinto Kagaku Co., Ltd.), and a load of 0.25 kg / cm ² is applied on the surface of the sample antifogging film. The flannel cloth was reciprocated 1000 times while adding, and the appearance of the film surface was visually observed and evaluated according to the following criteria.
◎: No change in appearance ○: Slightly unclear and very shallow scratches can be confirmed.
Δ: A clear flaw can be visually confirmed.
X: Peeling of the antifogging film is observed.

(6) Abrasion resistance Using a Taber INDUSTRIES Taber abrasion tester “5130”, an abrasion test was performed under the conditions of a load of 250 g and a rotation of 500, and the change in haze value ΔHz (%) before and after the test was measured. . The haze value was measured using a haze meter (“HZ-1S” manufactured by Suga Test Instruments Co., Ltd.). Abrasion resistance was evaluated according to the following criteria.
A: ΔHz was 6% or less.
A: ΔHz was more than 6% and 10% or less.
X: At least one of ΔHz exceeding 10% and film peeling occurred.

(7) Light straightness at the time of water droplet condensation Similar to the anti-fogging evaluation of (4) above, a sample is placed on hot water and cloudiness is observed on the entire surface exposed to water vapor, that is, water droplets are condensed. Hold until. Then, the haze rate at the time of water droplet condensation was measured immediately using the haze meter used in the above (6). The straightness of light during water droplet condensation was evaluated according to the following criteria.
A: The haze ratio was 15% or less.
A: The haze ratio was more than 15% and 35% or less.
X: The haze ratio was more than 35%.

Example 1
Polyvinyl acetal resin-containing solution (Sekisui Chemical Co., Ltd. “ESREC KX-5”, solid content 8 mass%, acetalization degree 9 mol%, including acetal structure derived from benzaldehyde) 62.5 mass%, n-hexyltri 0.376% by mass of methoxysilane (HTMS, “KBM-3063” manufactured by Shin-Etsu Silicone), 0.141% by mass of 3-glycidoxypropyltrimethoxysilane (GPTMS, “KBM-403” manufactured by Shin-Etsu Silicone), tetra Ethoxysilane (TEOS, “KBE-04” manufactured by Shin-Etsu Silicone Co., Ltd.) 1.734% by mass, alcohol solvent (“SOLMIX AP-7” manufactured by Nippon Alcohol Industry) 19.606% by mass, purified water 15.625% by mass, Hydrochloric acid 0.01% by weight as an acid catalyst, leveling agent (“KP-341” manufactured by Shin-Etsu Silicone) The .008% by weight was placed in a glass container by stirring 3 hours at room temperature (25 ° C.), to prepare a antifogging film forming coating solution.

Next, the coating solution was applied by a flow coating method on a washed float plate glass (soda lime silicate glass, thickness 3.1 mm, size 100 × 100 mm) in an environment of room temperature 20 ° C. and relative humidity 30%. After drying for 10 minutes in the same environment, a (preliminary) heat treatment at 120 ° C. was performed. Thereafter, a high-temperature and high-humidity treatment was performed by applying the above-described atmosphere and time, and an additional heat treatment was also performed by applying the above-described atmosphere and time to prepare a sample.

(Example 2)
A sample was prepared in the same manner as in Example 1 except that the amount of tetraethoxysilane added was 1.387% by mass and the amount of alcohol solvent added was 19.953% by mass.

(Example 3)
Without adding 3-glycidoxypropyltrimethoxysilane, the addition amount of n-hexyltrimethoxysilane was 0.37% by mass, the addition amount of tetraethoxysilane was 1.04% by mass, and the addition amount of alcohol solvent was 20%. An antifogging article was produced in the same manner as in Example 1 except that .44% by mass, the amount of purified water added was 15.63% by mass, and the amount of leveling agent added was 0.01% by mass. .

Example 4
Instead of 0.376% by mass of n-hexyltrimethoxysilane, 0.27% by mass of methyltriethoxysilane (MTES, “KBE-13” manufactured by Shin-Etsu Silicone Co., Ltd.) was used. 0.05 mass%, tetraethoxysilane addition amount 0.69 mass%, alcohol solvent addition amount 18.85 mass%, purified water addition amount 17.63 mass%, leveling agent addition amount A sample was produced in the same manner as in Example 1 except that the content was 0.01% by mass.

(Example 5)
The amount of the alcohol solvent added was 20.88% by mass, the amount of purified water added was 15.63% by mass, the amount of nitric acid added was 0.01% by mass, and the surface conditioner (“BYK-307” manufactured by BYK Japan KK) ) A sample was prepared in the same manner as in Example 4 except that 0.01% by mass was further added.

(Comparative Example 1)
Instead of 0.27% by mass of methyltriethoxysilane, 0.21% by mass of 3-glycidoxypropyltrimethoxysilane was used, the amount of tetraethoxysilane added was 1.04% by mass, and the amount of alcohol solvent added was 20. A sample was produced in the same manner as in Example 5 except that the content was 59% by mass.

Tables 1 and 2 show the components of the antifogging film and the evaluation results of the samples. In Table 1, the mass part of each component is shown with the mass part of the water absorbent resin as 100.

Claims

A windshield suitable for arrangement of an information acquisition device that receives light incident from the outside of the vehicle into the vehicle and acquires information outside the vehicle,
A glass plate,
An antifogging film formed on the inner surface of the glass plate,
The antifogging film includes a water repellent group and a metal oxide component,
The surface on the inside of the vehicle has an information acquisition region through which the light incident on the information acquisition device is transmitted and the information acquisition device is arranged to face the surface.
The windshield, wherein the antifogging film is formed so as to cover at least the information acquisition region.
Further comprising a shielding film that makes a part of the glass plate opaque.
2. The windshield according to claim 1, wherein at least a part of the shielding area on which the shielding film is formed is disposed between the fluoroscopic area for the driver to visually recognize the outside of the vehicle and the information acquisition area.
Further comprising a shielding film that makes a part of the glass plate opaque.
The information acquisition region is located in an opening provided in the shielding film,
3. The window according to claim 1, wherein a see-through area for a driver to visually recognize the outside of the vehicle and the information acquisition area are separated on the surface inside the vehicle by the shielding area on which the shielding film is formed. shield.
The windshield according to claim 2 or 3, wherein the antifogging film is formed so as not to cover the see-through region.
In a state where the windshield is installed on a vehicle body, the antifogging film has a film thickness distribution in which a film thickness at a lower end portion of the information acquisition region is larger than a film thickness at an upper end portion of the information acquisition region. Item 5. The windshield according to any one of Items 1 to 4.
In a state where the windshield is installed on a vehicle body, the antifogging film has a film thickness distribution in which a film thickness at an upper end portion of the information acquisition region is larger than a film thickness at a lower end portion of the information acquisition region. Item 5. The windshield according to any one of Items 1 to 4.
The antifogging film further includes a water absorbent resin,
The windshield according to any one of claims 1 to 6, wherein the water absorbent resin is at least one selected from the group consisting of a urethane resin, an epoxy resin, an acrylic resin, a polyvinyl acetal resin, and a polyvinyl alcohol resin. .
The water absorbent resin is a polyvinyl acetal resin,
The windshield according to claim 7, wherein the degree of acetalization of the polyvinyl acetal resin is 2 to 40 mol%.
The windshield according to claim 8, wherein the polyvinyl acetal resin includes an acetal structure derived from an aromatic aldehyde.
The antifogging film is based on 100 parts by mass of the water absorbent resin.
0.1 to 60 parts by mass of the metal oxide component,
0.05 to 10 parts by mass of the water repellent group,
The windshield according to any one of claims 7 to 9, further comprising:
The windshield according to any one of claims 1 to 9, wherein the antifogging film is a single layer film.
The water repellent group is a chain alkyl group having 1 to 8 carbon atoms,
The water repellent group is directly bonded to the metal atom constituting the metal oxide component,
The windshield according to any one of claims 1 to 11, wherein the metal atom is silicon.
The windshield according to claim 12, wherein the water repellent group is a chain alkyl group having 4 to 8 carbon atoms.
A metal oxide component derived from a hydrolyzable metal compound or a hydrolyzate of a hydrolyzable metal compound, wherein at least a part of the metal oxide component is added to a coating solution for forming the antifogging film. Because
The hydrolyzable metal compound is at least one selected from the hydrolyzable metal compound having a water-repellent group and the hydrolyzable metal compound not having the water-repellent group. The windshield according to item 1.
The windshield according to claim 14, wherein the hydrolyzable metal compound having no water repellent group contains at least one selected from tetraalkoxysilane and a silane coupling agent.
The windshield according to any one of claims 1 to 15, wherein a contact angle of water on the surface of the antifogging film is 90 degrees or more.
The windshield according to any one of claims 1 to 16, wherein the antifogging film is directly formed on the surface of the glass plate.