JP7679678B2 - Laminated glass for automobile windows and automobiles - Google Patents

Description

This disclosure relates to laminated glass for automotive windows and automobiles.

There is a demand for technology that reduces the impact on people, such as pedestrians, when a car collides with them. For example, Patent Document 1 discloses technology in which, when an impact is applied to the cowl louvers and the area around the windshield, the rear end of the cowl louvers and the front end of the windshield, which are connected by a molding, are separated, thereby reducing the impact on people.

The curved glass sheet with a light-shielding film for vehicles described in Patent Document 2 includes a glass sheet and a light-shielding film formed on at least a part of a film-forming portion, which is a peripheral portion on one surface of the glass sheet. The light-shielding film is formed of a band-shaped film arranged on the outer side of the peripheral portion and a dot-shaped pattern film consisting of a plurality of dots arranged on the inner side of the band-shaped film.

JP 2017-213928 A International Publication No. 2007-052600

Laminated glass for automobile windows, such as windshields, is required to break appropriately in order to reduce the impact on people, such as pedestrians, when a car collides with them. For example, laminated glass for automobile windows is required to have a Head Injury Criterion (HIC) below a desired value. On the other hand, laminated glass for automobile windows is also required to allow automobile occupants to see the outside of the automobile.

One aspect of the present disclosure provides technology that allows vehicle occupants to see outside the vehicle while reducing the impact on a person during a collision between the vehicle and the person.

A laminated glass for automobile windows according to one embodiment of the present disclosure comprises, from the vehicle exterior side toward the vehicle interior side, a first glass sheet, an intermediate film, and a second glass sheet, in this order. A plurality of fired layers formed by firing glass powder are provided at intervals in a see-through area on the vehicle interior surface of the first glass sheet or the second glass sheet, which allows the vehicle occupants to view the outside of the vehicle. The fired layers have a circle equivalent diameter of 0.02 mm to 0.5 mm and a layer thickness of 0.002 mm to 0.3 mm.

According to one aspect of the present disclosure, it is possible to reduce the impact on a person during a collision between a vehicle and the person while allowing the vehicle occupants to see outside the vehicle.

FIG. 1 is a front view of an automobile equipped with a laminated glass according to one embodiment. FIG. 2 is a cross-sectional view showing a portion of a laminated glass according to an embodiment. FIG. 3 is a cross-sectional view showing an example of a fired layer formed on the first glass plate. FIG. 4 is a cross-sectional view showing an example of a fired layer formed on the second glass plate. FIG. 5 is a diagram showing an example of an arrangement pattern of a fired layer provided on a first glass sheet and a fired layer provided on a second glass sheet, as viewed from the vehicle interior side.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the same or corresponding configurations in each drawing are given the same reference numerals, and descriptions thereof may be omitted. In the specification, "~" indicating a range of values means that the values before and after it are included as the lower and upper limits.

As shown in FIG. 1, an automobile 100 includes a laminated automobile window glass 1 and a vehicle body 2 including an opening in which the laminated automobile window glass 1 is attached. Hereinafter, the laminated automobile window glass 1 will also be referred to simply as laminated glass 1. The laminated automobile window glass 1 is, for example, a windshield, but it may also be window glass other than a windshield, for example, a side glass, a rear glass, or a roof glass.

As shown in FIG. 2, the laminated glass 1 comprises, in this order from the exterior side to the interior side of the vehicle, a first glass sheet 10, an intermediate film 30, and a second glass sheet 20. The intermediate film 30 bonds the first glass sheet 10 and the second glass sheet 20 together. The first glass sheet 10 has a first surface 11 that faces the exterior side of the vehicle, and a second surface 12 that faces the interior side of the vehicle. The second glass sheet 20 has a third surface 21 that faces the exterior side of the vehicle, and a fourth surface 22 that faces the interior side of the vehicle.

The first glass plate 10 and the second glass plate 20 may be made of the same material or different materials. The material of the first glass plate 10 and the second glass plate 20 is preferably inorganic glass. Examples of inorganic glass include soda lime silicate glass, aluminosilicate glass, borate glass, lithium aluminosilicate glass, and borosilicate glass. The method of forming the inorganic glass into a plate shape is not particularly limited, but may be, for example, the float method.

The first glass sheet 10 and the second glass sheet 20 may be untempered glass (raw glass). Untempered glass is glass that is made by forming molten glass into a sheet shape and slowly cooling it, and has not been subjected to tempering treatments such as air-cooling tempering and chemical tempering. Untempered glass is less likely to develop net-like or spider web-like cracks when broken by impact, and can ensure visibility for occupants.

The first glass plate 10 and the second glass plate 20 may have the same thickness or different thicknesses. The thickness of the first glass plate 10 is, for example, 1.1 mm or more and 3.5 mm or less. The thickness of the second glass plate 20 is, for example, 0.5 mm or more and 2.3 mm or less. Furthermore, the thickness of the entire laminated glass 1 is 2.3 mm or more and 8.0 mm or less.

The material of the intermediate film 30 is not particularly limited, but is preferably a thermoplastic resin. Examples of the material of the intermediate film 30 include thermoplastic resins that have been used for various applications, such as plasticized polyvinyl acetal resins, plasticized polyvinyl chloride resins, saturated polyester resins, plasticized saturated polyester resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, cycloolefin polymer resins, and ionomer resins. In addition, a resin composition containing a modified block copolymer hydrogenated product described in Japanese Patent No. 6065221 can also be preferably used. Among these, plasticized polyvinyl acetal resins are preferably used because they have an excellent balance of various performances such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. The above thermoplastic resins may be used alone or in combination of two or more. "Plasticized" in the above plasticized polyvinyl acetal resin means that it has been plasticized by adding a plasticizer. The same applies to other plasticized resins.

The material of the intermediate film 30 may be a resin that does not contain a plasticizer, such as an ethylene-vinyl acetate copolymer resin. Examples of the polyvinyl acetal resin include polyvinyl formal resin obtained by reacting polyvinyl alcohol (PVA) with formaldehyde, polyvinyl acetal resin in the narrow sense obtained by reacting PVA with acetaldehyde, and polyvinyl butyral resin (PVB) obtained by reacting PVA with n-butylaldehyde. In particular, PVB is a suitable material because it has an excellent balance of various properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. The above resins may be used alone or in combination of two or more.

The intermediate film 30 may have either a single-layer structure or a multi-layer structure. The intermediate film 30 may have a function other than adhesion. For example, the intermediate film 30 may have one or more layers selected from a sound-insulating layer, a colored transparent layer, an ultraviolet-cutting layer, an infrared-cutting layer, and the like.

The thickness of the intermediate film 30 is 0.5 mm or more from the viewpoint of adhesiveness. Also, the thickness of the intermediate film 30 is 3 mm or less from the viewpoint of light weight and ease of handling. The thickness of the intermediate film 30 may be constant or may vary depending on the position. For example, when an image of a head-up display is projected onto the laminated glass 1, the thickness of the intermediate film 30 increases from the bottom to the top in order to suppress the occurrence of double images. The intermediate film 30 is formed in a wedge shape, and the wedge angle is, for example, 1.0 mrad or less.

The manufacturing method of the laminated glass 1 includes, for example, the following steps (A) to (C). (A) The first glass sheet 10 and the second glass sheet 20 are laminated with the interlayer film 30 interposed therebetween to produce a laminate. (B) The laminate is placed inside a rubber bag, and the rubber bag is heated while reducing the pressure inside the rubber bag, and the first glass sheet 10 and the second glass sheet 20 are bonded with the interlayer film 30. The air pressure inside the rubber bag is, for example, -100 kPa to -65 kPa based on atmospheric pressure. The heating temperature of the rubber bag is, for example, 70°C to 110°C. (C) The laminate removed from the rubber bag is heated at 100°C to 150°C and compressed at a pressure of 0.6 MPa to 1.3 MPa. For example, an autoclave is used for the compression. Note that the manufacturing method of the laminated glass 1 may be a general method, and does not have to include the above step (C).

As shown in FIG. 2, the laminated glass 1 is curved, for example, entirely or partially, so as to be convex toward the outside of the vehicle. The laminated glass 1 is compound-curved, i.e. curved in the front-rear and up-down directions of the vehicle, but may also be single-curved, i.e. curved only in the front-rear or up-down directions. The radius of curvature of the laminated glass 1 is, for example, 200 mm to 300,000 mm.

The first glass sheet 10 and the second glass sheet 20 are bent before the above step (A). The bending is performed in a state where the glass is softened by heating. The heating temperature of the glass during bending is, for example, 550°C to 700°C. The first glass sheet 10 and the second glass sheet 20 may be bent separately, or may be overlapped and bent simultaneously. The bending may include gravity forming or press forming, or may include both.

As shown in FIG. 2, the laminated glass 1 is required to break appropriately in order to reduce the impact on a person 200 such as a pedestrian when the automobile 100 collides with the person 200. For example, the laminated glass 1 is required to have a Head Injury Criterion (HIC) of a desired value or less (for example, 1000 or less, preferably 650 or less). On the other hand, the laminated glass 1 is also required to allow the occupants of the automobile 100 to see the outside of the automobile 100.

When the automobile 100 collides with the person 200, the laminated glass 1 is pushed from the outside of the vehicle toward the inside of the vehicle. As a result, tensile stress is generated in the second surface 12, which is the surface of the first glass sheet 10 facing the inside of the vehicle, and the second glass sheet 20 breaks from a defect in the second surface 12. Tensile stress is also generated in the fourth surface 22, which is the surface of the second glass sheet 20 facing the inside of the vehicle, and the second glass sheet 20 breaks from a defect in the fourth surface 22. In both the first glass sheet 10 and the second glass sheet 20, the crack propagates from the inside of the vehicle to the outside.

In one aspect of the present disclosure, as shown in FIG. 3, a fired layer 50 is formed in the see-through area of the second surface 12 of the first glass sheet 10, thereby adjusting the strength of the first glass sheet 10 to an appropriate value. In another aspect of the present disclosure, as shown in FIG. 4, a fired layer 50 is formed in the see-through area of the fourth surface 22 of the second glass sheet 20, thereby adjusting the strength of the second glass sheet 20 to an appropriate value. The see-through area is an area that allows the occupants of the automobile 100 to view the outside of the automobile 100. The see-through area is surrounded by a light-shielding area. The light-shielding area is an area that is covered with a light-shielding layer 40.

Below, we will explain the case where the light-shielding layer 40 and the fired layer 50 are formed on the fourth surface 22 of the second glass plate 20. The case where the light-shielding layer 40 and the fired layer 50 are formed on the second surface 12 of the first glass plate 10 is similar, so we will omit the explanation. The light-shielding layer 40 only needs to be formed on at least one of the second surface 12 and the fourth surface 22. The same applies to the fired layer 50. For example, only the fired layer 50 may be provided on the second surface 12, and only the light-shielding layer 40 may be provided on the fourth surface 22.

The light-shielding layer 40 is formed by firing a dark pigment and glass powder. Specifically, a paste containing a dark pigment and glass powder is applied, and the paste is fired to form the light-shielding layer 40. The color of the dark pigment is, for example, black, gray, or brown. The method of applying the paste is not particularly limited, but may be, for example, screen printing.

The light-shielding layer 40 is formed in a band shape on the periphery of the fourth surface 22 of the second glass plate 20, for example, in a range of 10 mm to 300 mm from the periphery of the fourth surface 22 (see FIG. 5). The light-shielding layer 40 blocks ultraviolet rays and suppresses deterioration of the adhesive that bonds the laminated glass 1 and the vehicle body 2. The adhesive is, for example, urethane.

The light-shielding layer 40 is fired when the second glass sheet 20 is bent to shorten the manufacturing process of the laminated glass 1, but it may also be fired before the second glass sheet 20 is bent. In either case, the glass powder contained in the light-shielding layer 40 bonds with the second glass sheet 20, and the light-shielding layer 40 and the second glass sheet 20 are integrated together.

The fired layer 50 is formed by firing glass powder. Specifically, a paste containing glass powder is applied and then fired to form the fired layer 50. The method of applying the paste is not particularly limited, but may be screen printing, for example. When the glass powder is heated, it bonds to each other and forms a porous structure. Therefore, the surface roughness of the fired layer 50 is greater than the surface roughness of the second glass plate 20.

In this specification, the surface roughness is the arithmetic mean roughness as defined in Japanese Industrial Standard JIS B0601:1994, and is measured, for example, using a contact type surface roughness measuring device (NX001) manufactured by Tokyo Seimitsu. The surface roughness of the fired layer 50 is, for example, 100 nm to 5000 nm, and preferably 500 nm to 800 nm. On the other hand, the surface roughness of the second glass plate 20 is, for example, 15 nm or less, and preferably 10 nm or less.

The fired layer 50 is fired when the second glass sheet 20 is bent to shorten the manufacturing process of the laminated glass 1, but it may be fired before the second glass sheet 20 is bent. In either case, the glass powder contained in the fired layer 50 bonds with the second glass sheet 20, and the fired layer 50 and the second glass sheet 20 are integrated.

Because the surface roughness of the fired layer 50 is greater than the surface roughness of the second glass plate 20, when the fired layer 50 is formed on the fourth surface 22 of the second glass plate 20, a large defect is formed on the fourth surface 22. If the defect is large, stress is likely to concentrate and cracks are likely to occur. Therefore, the second glass plate 20 is likely to break.

The fired layer 50 has, for example, a circle equivalent diameter D of 0.02 mm to 0.5 mm and a layer thickness T of 0.002 mm to 0.3 mm. According to the Japanese Automotive Standards Organization (JASO) standard, the presence of black spots with a diameter of 0.5 mm or less in the see-through area is permitted.

The see-through area is an area that allows the occupants of the automobile 100 to see the outside of the automobile 100, so it is generally considered desirable for it to be free of black spots and the like. In contrast, the technology disclosed herein imparts defects of a size that are barely noticeable to the occupants of the automobile 100 to the see-through area, making the laminated glass 1 more likely to break while still maintaining transparency.

When viewed from a direction perpendicular to the first surface 11 of the first glass plate 10, the shape of the fired layer 50 is, for example, circular, elliptical, rectangular, or polygonal. In any case, if the circle-equivalent diameter D of the fired layer 50 is 0.5 mm or less, the visibility is good. The circle-equivalent diameter D is preferably 0.3 mm or less.

On the other hand, if the circle equivalent diameter D of the fired layer 50 is 0.02 mm or more, the size of the fired layer 50 is large and the second glass plate 20 is likely to break. The circle equivalent diameter D is preferably 0.1 mm or more.

If the layer thickness T of the fired layer 50 is 0.3 mm or less, visible light can easily pass through and the transparency is good. The layer thickness T is preferably 0.1 mm or less.

On the other hand, if the layer thickness T of the fired layer 50 is 0.002 mm or more, the size of the fired layer 50 is large and the second glass plate 20 is likely to break. The layer thickness T is preferably 0.05 mm or more.

The layer thickness T of the fired layer 50 may be smaller than the layer thickness of the light-shielding layer 40, as shown in FIG. 4. The visible light transmittance of the fired layer 50 can be made higher than the visible light transmittance of the light-shielding layer 40. This is particularly advantageous when the fired layer 50 and the light-shielding layer 40 are formed from the same paste.

The fired layer 50 may be formed by firing glass powder and dark pigment, or may be formed using the same paste as the light-shielding layer 40. In this case, there are fewer types of paste, making it easier to manage the paste. Also, in this case, the paste can be applied simultaneously to the area where the fired layer 50 is to be formed and the area where the light-shielding layer 40 is to be formed, reducing the number of times the paste is applied.

The fired layer 50 may be formed by firing glass powder and metal powder. The metal powder is, for example, silver powder. The metal powder is not limited to silver powder and may be, for example, copper powder. In this case, the fired layer 50 has electrical conductivity.

The fired layer 50 may be formed using the same paste as the conductive layer (not shown). The conductive layer is formed on the light-shielding layer 40 and constitutes an antenna or a heater. The conductive layer is fired simultaneously with the light-shielding layer 40.

When the fired layer 50 and the conductive layer are formed using the same paste, the number of types of paste is small and paste management is easy. In this case, the paste can be applied simultaneously to the area where the fired layer 50 is formed and the area where the conductive layer is formed, reducing the number of times the paste is applied.

The fired layer 50 may not contain dark pigments or metal powder, and may be formed using a paste different from that used for the light-shielding layer 40 and the conductive layer. If the fired layer 50 does not contain dark pigments or metal powder, it will be more transparent than if it contains dark pigments or metal powder, improving transparency.

The firing layers 50 are provided at intervals in the see-through region. The firing layers 50 may be provided, for example, in a first region surrounded by a first virtual line L1 100 mm inward from the boundary line L3 between the light-shielding region and the see-through region, and may be distributed throughout the first region. The firing layers 50 may also be provided in a second region surrounded by a second virtual line L2 25 mm inward from the boundary line L3 between the light-shielding region and the see-through region, and may be distributed throughout the second region.

In addition, a circular or semicircular dot pattern with a diameter of 0.5 mm to 2.5 mm and made of the same material as the light-shielding layer 40 may be formed in the see-through region near the boundary line L3 between the light-shielding region and the see-through region. This dot pattern is formed inside the light-shielding region covered by the strip-shaped light-shielding layer 40, and is formed in the see-through region.

The fired layer 50 is arranged, for example, at the lattice points of a square lattice. The lattice is not limited to a square lattice, and may be a regular triangular lattice or a regular hexagonal lattice. The lattice may also be a lattice in which a regular polygon is distorted in the vertical or horizontal direction, for example, a rectangular lattice.

The pitch P of the fired layer 50 is, for example, 10 mm to 200 mm. The pitch P is the distance from each point to the nearest point. If the pitch P is 200 mm or less, the number of crack starting points is large, and cracks are likely to occur near the point of impact of the person 200. The pitch P is preferably 100 mm or less.

On the other hand, if the pitch P of the fired layer 50 is 10 mm or more, the transparent image is less likely to be distorted and the transparency is good. The pitch P is preferably 50 mm or more.

As shown in FIG. 5, when viewed from a direction perpendicular to the first surface 11 of the first glass plate 10, it is preferable that the fired layer 50-2 on the second glass plate 20 is located within 100 mm (preferably within 50 mm) of the fired layer 50-1 on the first glass plate 10. When the automobile 100 and the person 200 collide, the first glass plate 10 and the second glass plate 20 break at points close to each other, so that the impact is absorbed in a short time.

When viewed from a direction perpendicular to the first surface 11 of the first glass plate 10, the fired layer 50-1 on the first glass plate 10 and the fired layer 50-2 on the second glass plate 20 are arranged in a staggered configuration, but the arrangement is not limited to a staggered configuration.

When viewed from a direction perpendicular to the first surface 11 of the first glass plate 10, it is preferable that the fired layer 50-1 provided on the first glass plate 10 and the fired layer 50-2 provided on the second glass plate 20 overlap. The fired layer 50-1 provided on the first glass plate 10 and the fired layer 50-2 provided on the second glass plate 20 do not have to completely overlap, but only need to overlap at least partially.

The laminated glass for automobile windows and automobiles according to the present disclosure have been described above, but the present disclosure is not limited to the above-mentioned embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present disclosure.

Reference Signs List 1: Laminated glass for automobile windows 10: First glass plate 20: Second glass plate 30: Interlayer 40: Light-shielding layer 50: Fired layer

Claims (10)

A laminated glass for automobile windows, comprising, in this order from an exterior side to an interior side of a vehicle, a first glass sheet, an interlayer film, and a second glass sheet,
A plurality of fired layers formed by firing glass powder are provided at intervals in a see-through area on the vehicle-interior surface of the first glass plate or the second glass plate, the see-through area allowing an occupant of the vehicle to view the outside of the vehicle,
a light-shielding layer formed by firing a glass powder and a dark pigment is provided in a light-shielding region surrounding the see-through region on the vehicle interior surface of the first glass plate or the second glass plate;
The fired layer has a circle equivalent diameter of 0.02 mm to 0.5 mm and a layer thickness of 0.002 mm to 0.3 mm. The laminated glass for automobile windows according to claim 1, wherein the pitch of the fired layers on the vehicle interior side of the first glass sheet or the second glass sheet is 10 mm to 200 mm. 3. The laminated glass for an automobile window according to claim 1 , wherein the fired layer is provided in a first region surrounded by a first imaginary line 100 mm inward from a boundary line between the light-shielding region and the see-through region. The laminated glass for automobile windows according to any one of claims 1 to 3 , wherein the fired layer has a thickness smaller than that of the light-shielding layer. The laminated glass for automobile windows according to any one of claims 1 to 4 , wherein the fired layer is formed by firing the glass powder and the dark pigment. The laminated glass for automobile windows according to any one of claims 1 to 4 , wherein the fired layer is formed by firing the glass powder and the metal powder. The laminated glass for automobile windows according to any one of claims 1 to 4 , wherein the fired layer does not contain dark pigments and metal powders. The laminated glass for an automobile window according to any one of claims 1 to 7 , wherein the fired layer is provided on a surface of the first glass plate facing an interior side of the vehicle, and the fired layer is provided on a surface of the second glass plate facing an interior side of the vehicle. 9. The laminated glass for automobile windows according to claim 8, wherein the fired layer provided on the second glass plate is present within a range of 100 mm from the fired layer provided on the first glass plate when viewed from a direction perpendicular to the vehicle exterior surface of the first glass plate. A laminated glass for automobile windows according to any one of claims 1 to 9 ,
A vehicle body including an opening into which the laminated glass for automobile windows is to be attached;
A motor vehicle equipped with:

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