CN116438089A

CN116438089A - Laminated glass, method for producing PVB layer, and method for producing laminated glass

Info

Publication number: CN116438089A
Application number: CN202180071609.6A
Authority: CN
Inventors: 横手辰郎; 小森敦; 若林浩和; 定金骏介; 西泽佑介
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2020-10-22
Filing date: 2021-10-22
Publication date: 2023-07-14
Also published as: WO2022085787A1; JPWO2022085787A1

Abstract

The invention can inhibit the visibility of HUD image from decreasing. A laminated glass (1) is provided with: a first glass substrate (12), a second glass substrate (14), a reflective layer (16) disposed between the first glass substrate (12) and the second glass substrate (14), and a PVB layer (20) disposed between the second glass substrate (14) and the reflective layer (16) and formed of a polyvinyl butyral resin. The PVB layer (20) of the laminated glass (1) has a thickness (D5) of 2-25 [ mu ] m, the laminated glass (1) has a longitudinal radius of curvature of 20000mm or less, the laminated glass (1) has a transverse radius of curvature of 10000mm or less, and the laminated glass (1) has a bubble remaining rate of 2% or less.

Description

Laminated glass, method for producing PVB layer, and method for producing laminated glass

Technical Field

The present invention relates to laminated glass, a method for producing a PVB layer, and a method for producing laminated glass.

Background

In recent years, introduction of a Head Up Display (HUD) for reflecting an image onto glass of a vehicle or the like and displaying predetermined information in a visual field of a driver is advancing. For example, patent document 1 describes a laminated glass in which a half mirror is provided between an inner surface side glass and an outer surface side glass.

Patent document 1: japanese patent laid-open publication No. 2019-15783

Disclosure of Invention

Technical problem to be solved by the invention

Such laminated glass for displaying HUD images is required to suppress degradation in visibility of the displayed HUD images.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a laminated glass, a method for producing a PVB layer, and a method for producing a laminated glass, each of which can suppress a decrease in visibility of a HUD image.

Means for solving the problems

In order to solve the above problems and achieve the object, a laminated glass of the present disclosure has: the laminated glass comprises a first glass substrate, a second glass substrate, a reflecting layer arranged between the first glass substrate and the second glass substrate, and a PVB layer arranged between the second glass substrate and the reflecting layer and formed by polyvinyl butyral resin, wherein the thickness (D5) of the PVB layer is more than or equal to 2 mu m and less than or equal to 25 mu m, the longitudinal curvature radius of the laminated glass is less than or equal to 20000mm, the transverse curvature radius of the laminated glass is less than or equal to 10000mm, and the bubble residual rate of the laminated glass is less than or equal to 2%.

To solve the above problems and achieve the object, a method for manufacturing a PVB layer of the present disclosure includes: and a step of forming a PVB layer, which is a layer of the polyvinyl butyral resin, having a thickness of 30 [ mu ] m or less, a maximum height Rz of the substrate side surface of 5 [ mu ] m or more, and a ratio of the maximum height Rz to the thickness of less than 0.95, by drying the coating liquid.

In order to solve the above problems and achieve the object, a method for manufacturing a laminated glass of the present disclosure is to laminate the PVB layer, the reflective layer, the first glass substrate, and the second glass substrate manufactured by the method for manufacturing a PVB layer to manufacture a laminated glass.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the decline in visibility of the HUD image can be suppressed.

Drawings

Fig. 1 is a schematic view of a laminated glass according to the present embodiment.

Fig. 2 is a schematic cross-sectional view of the laminated glass of the present embodiment.

Fig. 3 is an explanatory diagram of the bubble remaining ratio.

Fig. 4 is an illustration of a method of making a PVB layer.

Fig. 5 is a schematic diagram showing PVB layers prior to lamination.

Fig. 6 is an explanatory diagram of a method for manufacturing a laminated glass.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention includes embodiments in which the respective embodiments are combined. Furthermore, the numerical values include rounded ranges.

(laminated glass)

Fig. 1 is a schematic view of a laminated glass according to the present embodiment. The laminated glass 1 of the present embodiment shown in fig. 1 is mounted on a vehicle. The laminated glass 1 is a window member suitable for a vehicle windshield, in other words, a windshield that is a vehicle windshield. The interior (in-vehicle) of a vehicle is, for example, a cabin provided with a driver's seat. However, the use of the laminated glass 1 is not limited to the front window glass of the vehicle, and may be applied to other parts of the vehicle. Hereinafter, the upper edge of the laminated glass 1 is referred to as an upper edge 1a, the lower edge is referred to as a lower edge 1b, one side edge is referred to as a side edge 1c, and the other side edge is referred to as a side edge 1d. The upper edge 1a is an edge located on the upper side in the vertical direction when the laminated glass 1 is mounted on a vehicle. The lower edge 1b is an edge located at a lower side in the vertical direction when the laminated glass 1 is mounted on a vehicle. The side edge 1c is an edge portion located on one side when the laminated glass 1 is mounted on a vehicle. The side edge 1d is an edge portion located on the other side when the laminated glass 1 is mounted on a vehicle.

Next, the direction from the lower edge 1b toward the upper edge 1a in the direction parallel to the surface of the laminated glass 1 is referred to as the Y direction (longitudinal direction), and the direction from the side edge 1c toward the side edge 1d is referred to as the X direction (lateral direction). In this embodiment, the X direction is orthogonal to the Y direction. The direction perpendicular to the surface of the laminated glass 1, that is, the thickness direction of the laminated glass 1 is referred to as the Z direction. The Z direction is, for example, a direction from the vehicle outside toward the vehicle inside when the laminated glass 1 is mounted on the vehicle. The X direction and the Y direction are along the surface of the laminated glass 1, but may be directions that contact the surface of the laminated glass 1 at the center point O of the laminated glass 1 when the surface of the laminated glass 1 is curved, for example. The center point O is the center position of the laminated glass 1 when the laminated glass 1 is viewed from the Z direction.

The laminated glass 1 has a light-transmitting region A1 and a light-shielding region A2. The light transmitting region A1 is a region occupying the central portion of the laminated glass 1 as viewed from the Z direction, and is a region for securing the driver's visual field. The light transmitting region A1 is a region transmitting visible light. The light shielding region A2 is a region formed around the light transmitting region A1 as viewed from the Z direction. The light shielding region A2 is a region that shields visible light. In the light shielding region A2, a far infrared transmission region in which a far infrared camera is provided through far infrared rays, a visible light transmission region in which a visible camera is provided through visible light, and the like may be formed.

A HUD region AH is formed in the light-transmitting region A1. The HUD area AH is an area that irradiates light from a projector, not shown, and displays HUD images, which are images projected from the projector. The projector is a device that projects an image for HUD onto the laminated glass 1, that is, a projector, for example. The projection device is provided at a position overlapping with the HUD area AH when viewed from the optical axis direction of the projection device. The HUD area AH is formed closer to the X direction side than the center point O, and is formed closer to the side edge portion 1d side than the center point O and is located closer to the lower edge portion 1b side in the example of fig. 1. However, the HUD area AH may be formed at a position and a size, for example, closer to the side edge 1c than the center point O. Further, a plurality of HUD areas AH may be formed. The HUD area AH may be a range in which light from a mirror constituting the HUD is irradiated to a windshield when the mirror constituting the HUD disposed in the vehicle is rotated in a view (EyeBox) based on SAE-J1757-2 (2018).

The radius of curvature in the Y direction (longitudinal direction) of the laminated glass 1 is 20000mm or less, and preferably 4000mm or more. The laminated glass 1 more preferably has a Y-direction curvature radius of 6000mm to 20000 mm. The laminated glass 1 has an X-direction (transverse) radius of curvature of 10000mm or less, preferably 1000mm or more. The radius of curvature in the X direction of the laminated glass 1 is more preferably 1500mm to 6000 mm. The Y-direction curvature radius here means a curvature radius of a curve extending in the Y-direction along the surface of the laminated glass 1, and the X-direction curvature radius means a curvature radius of a curve extending in the X-direction along the surface of the laminated glass 1. The radius of curvature of the entire region of the laminated glass 1 is preferably within the above-described range of the radius of curvature. The radius of curvature is obtained by measuring the shape at a predetermined pitch, for example, at a pitch of 20mm, over the entire region of the laminated glass 1 and converting the measured shape into the radius of curvature in the Y direction or the X direction.

The length in the Y direction of the laminated glass 1, that is, the length in the Y direction from the upper edge portion 1a to the lower edge portion 1b is preferably 200mm to 2500mm, more preferably 200mm to 2000mm, and still more preferably 200mm to 1500 mm. The Y-direction length of the laminated glass 1 herein refers to the Y-direction length at the longest portion. The length in the X direction of the laminated glass 1, that is, the length in the X direction from the side edge portion 1c to the side edge portion 1d is preferably 200mm to 2500mm, more preferably 200mm to 2300mm, and even more preferably 200mm to 2000 mm. The X-direction length of the laminated glass 1 herein refers to the X-direction length at the longest portion.

Fig. 2 is a schematic cross-sectional view of the laminated glass of the present embodiment. Fig. 2 is a cross-sectional view of the laminated glass 1 as viewed from the Y direction. As shown in fig. 2, the laminated glass 1 has a first glass substrate 12, a second glass substrate 14, a reflective layer 16, an interlayer 18, a PVB layer 20, and a light shielding layer 22. In the laminated glass 1, the first glass substrate 12, the interlayer 18, the reflection layer 16, the PVB layer 20, the second glass substrate 14, and the light shielding layer 22 are laminated in this order in the Z direction. The laminated glass 1 displays a HUD image by reflecting light from a projector device by a reflection layer 16 formed on the HUD region AH.

(glass substrate)

The first glass substrate 12 is a glass substrate on the vehicle exterior side. As the first glass substrate 12, for example, soda lime glass, aluminosilicate glass, and organic glass can be used, but is not limited thereto. The thickness D1 of the first glass substrate 12 is preferably 1.8mm to 3.0mm, more preferably 1.9mm to 2.3 mm. By setting the thickness D1 of the first glass substrate 12 within this range, the weight increase can be suppressed and the formability can be reduced while the resistance to flying stones and the like is suitably maintained. The thickness D1 is the length of the first glass substrate 12 in the Z direction, and is the length in the Z direction unless otherwise specified.

The second glass substrate 14 is a glass substrate on the vehicle interior side. As the second glass substrate 14, for example, soda lime glass, aluminosilicate glass, or organic glass can be used as in the first glass substrate 12, but is not limited thereto. The thickness D2 of the second glass substrate 14 is preferably 0.3mm to 2.3mm, more preferably 0.4mm to 2.0 mm. When the thickness of the second glass base 14 is 0.3mm or more, handling at the time of manufacturing, assembling, and the like is easy. By setting the thickness D2 of the second glass substrate 14 within this range, it is possible to appropriately maintain the follow-up property with respect to the PVB layer without increasing the thickness D1 of the first glass substrate 12, and without causing a mismatch when the first glass substrate 12 and the second glass substrate 1 are laminated after bending to a planar shape.

(reflective layer)

The reflective layer 16 is disposed between the first glass substrate 12 and the second glass substrate 14 in the Z-direction. The reflective layer 16 is a layer that reflects light irradiated from the projection device to the HUD area AH. The reflective layer 16 is transparent to visible light. In the present embodiment, since P-polarized light is irradiated from the projection device, the reflection layer 16 can be said to be a P-polarized light reflection film that reflects light of the P-polarized light. The reflection layer 16 is formed by laminating a plurality of polymers having different refractive indexes in the Z direction, for example. The reflection layer 16 preferably has a reflectance of 5% or more of P-polarized light having an incident angle of brewster's angle in a state where the reflection layer 16 is enclosed in the laminated glass 1. The HUD image can be suitably recognized when the reflectance of P-polarized light is 5% or more. The reflective layer 16 is not limited to the P-polarized light reflective film, and may be, for example, a hologram film, a scattering type transparent screen, an antireflection film for HUD, or the like. For example, the reflection layer 16 may have a first layer (for example, a 1/4 wavelength plate) for converting incident P-polarized light into circularly polarized light and a second layer (for example, a cholesteric liquid crystal layer) for selectively reflecting circularly polarized light, and the first layer converts the circularly polarized light reflected by the second layer into P-polarized light and emits the P-polarized light.

The thickness D3 of the reflection layer 16 is preferably 25 μm or more and 200 μm or less, more preferably 40 μm or more and 100 μm or less. The thickness D3 within this range can appropriately reflect light from the projector and appropriately transmit external light. In the present embodiment, the reflection layer 16 is provided over the entire region of the laminated glass 1 as viewed in the Z direction, but may be provided only in the HUD region AH, for example. That is, the reflection layer 16 may be formed at least in the HUD region AH in the entire region of the laminated glass 1.

(intermediate layer)

An intermediate layer 18 is provided between the first glass substrate 12 and the reflective layer 16 in the Z-direction. The intermediate layer 18 is bonded to the first glass substrate 12 on the surface on the vehicle exterior side and to the reflective layer 16 on the surface on the vehicle interior side, thereby bonding the first glass substrate 12 and the reflective layer 16. The intermediate layer 18 is formed of PVB (Poly Vinyl Butyral), i.e., polyvinyl butyral resin. The polyvinyl butyral resin is, for example, a thermoplastic resin obtained by reacting polyvinyl alcohol with n-butyraldehyde.

The thickness D4 of the interlayer 18 is thicker than the thickness D5 of the PVB layer 20 described later. The thickness D4 of the intermediate layer 18 is preferably 0.3mm to 15mm, more preferably 0.3mm to 3mm, and still more preferably 0.7mm to 1 mm. The thickness of the intermediate layer 18 within this range can suppress an increase in weight while ensuring safety performance required as a laminated glass, and can suppress difficulty in handling at the time of manufacture, assembly, and the like.

The intermediate layer 18 is not limited to being formed of a polyvinyl butyral resin, and may be formed of any material such as EVA (Ethylene Vinyl Acetate, ethylene-vinyl acetate copolymer), COP (Cyclo Olefin Polymer, cyclic olefin polymer), or the like. The intermediate layer 18 may have a film having an ultraviolet light absorbing or infrared light absorbing function. The interlayer 18 may color a portion corresponding to the upper edge portion 1a of the laminated glass 1. The interlayer 18 may have three or more layers such as a sound-insulating PVB having a sound-insulating layer sandwiched between PVB layers. When the intermediate layer 18 has three or more layers, the thickness of the core layer positioned at the center in the thickness direction is 70 μm or more and 130 μm or less, more preferably 80 μm or more and 120 μm or less, and still more preferably 90 μm or more and 110 μm or less. The core layer having such a thickness can suppress the decrease in the sound insulation function of the intermediate layer 18.

(PVB layer)

A PVB layer 20 is disposed between the second glass substrate 14 and the reflective layer 16 in the Z-direction. The PVB layer 20 is bonded to the reflective layer 16 on the surface on the vehicle exterior side and to the second glass substrate 14 on the surface on the vehicle interior side, and thus has a function of bonding the reflective layer 16 to the second glass substrate 14. PVB layer 20 is formed from PVB, a polyvinyl butyral resin.

The thickness D5 of the PVB layer 20 is 2 μm or more and 25 μm or less, preferably 4 μm or more and 25 μm or less, and more preferably 4 μm or more and 20 μm or less. In this range, the thickness D5 can suppress the degradation of the adhesion to the second glass substrate 14 and the reflective layer 16 while suppressing the degradation of the visibility of the HUD image called orange peel. The thickness D5 here refers to the thickness of the PVB layer 20 in a state of being laminated on the laminated glass 1. As will be described later, the PVB layer 20 is laminated in a state in which irregularities are formed on the surface, and therefore, the reflective layer 16 and the second glass substrate 14 are pressed at the time of lamination to deform the surface having the irregularities, and the thickness D5 at the time of lamination is within the above-described numerical range.

In the present embodiment, the reflective layer 16 is formed over the entire area, and therefore the PVB layer 20 and the interlayer 18 are disposed across the reflective layer 16 over the entire area. However, in the case where the reflection layer 16 is not formed in the entire region, the PVB layer 20 and the interlayer 18 may be bonded to each other and integrated in the region where the reflection layer 16 is not formed.

(light-shielding layer)

The light shielding layer 22 is provided on the vehicle interior surface of the second glass substrate 14. The light shielding layer 22 is a layer that shields visible light. As the light shielding layer 22, for example, a ceramic light shielding layer or a light shielding film can be used. As the ceramic light shielding layer, for example, a ceramic layer made of a conventionally known material such as a black ceramic layer can be used. As the light shielding film, for example, a light shielding polyethylene terephthalate (PET) film, a light shielding polyethylene naphthalate (PEN) film, a light shielding polymethyl methacrylate (PMMA) film, and the like can be used. The light shielding layer 22 is not limited to the surface provided on the vehicle interior side of the second glass substrate 14, and may be provided on the surface of the vehicle exterior side of the first glass substrate 12, and may be formed between the first glass substrate 12 and the second glass substrate 14.

The light shielding region A2 is formed by providing the light shielding layer 22 on the laminated glass 1. That is, the light shielding region A2 is a region where the light shielding layer 22 is provided. The light-transmitting region A1 is a region where the

glass substrates

12 and 14 are not provided with the light-shielding layer 22.

(bubble survival rate)

Fig. 3 is an explanatory diagram of the bubble remaining ratio. The laminated glass 1 having the above-described structure has a bubble remaining ratio of 2% or less, preferably 1% or less, and more preferably 0%. When the bubble remaining rate is within this numerical range, deterioration in visibility can be suppressed. It is particularly preferable that the bubble remaining ratio in the HUD area AH is within this numerical range. The bubble remaining rate refers to the remaining degree of bubbles in the laminated glass 1. The bubbles are bubbles existing between the first glass substrate 12 and the second glass substrate 14, and are bubbles that remain, for example, in the manufacturing process between the PVB layer 20 and the second glass substrate 14 without being degassed. The size of the bubble monomer is preferably 2mm or less in diameter. The diameter of the air bubbles is 2mm or less, which is not likely to affect visibility. The diameter of the bubbles is more preferably 1mm or less. In the case where the bubble is not circular when viewed from the Z direction, the bubble may be treated as the diameter of the circumscribed circle of the bubble when viewed from the Z direction.

In the present embodiment, the region where the PVB layer 20 appears opaque and cloudy due to poor adhesion between the PVB layer 20 and the second glass substrate 14 is regarded as a collection of small bubbles. The areas of PVB layer 20 where the irregularities remain and appear to flash are also considered to be a collection of small bubbles. The area of such a region was calculated as the area of the bubble to determine the bubble remaining rate.

The bubble remaining rate will be described in more detail below. As shown in fig. 3, a region 1H is defined as a 100mm square region at an arbitrary position on the surface (in a plan view) of the laminated glass 1 as viewed from the Z direction. Light is irradiated onto the laminated glass 1, and the presence of bubbles in the region 1H is observed from the Z direction. For example, the reflection at the bubble may be confirmed by irradiating the laminated glass 1 with a high-intensity lamp, or the light scattering at the bubble may be confirmed by entering light from the end face of the laminated glass 1. The image of the bubble may be confirmed by irradiating light from the opposite side of the laminated glass 1, or the bubble may be confirmed by a laser microscope. For example, in fig. 3, the air bubbles c are present in the first region 1Ha, and the air bubbles are not present in the second region 1Hb which does not overlap with the first region 1 Ha. In this case, the bubble remaining rate in the first region 1Ha is obtained as the ratio of the area of all the bubbles c present in the region 1Ha to the area of the region 1Ha as viewed from the Z direction, and the bubble remaining rate in the region 1Hb is zero because there is no bubble c. Since the region 1H is an arbitrary region, the bubble remaining ratio of the laminated glass 1 as a whole is within the above range. However, the surface 1H is not necessarily required to measure the entire laminated glass 1, and only a square region of 100mm where the bubbles remain the most on the entire laminated glass 1 may be measured as the surface 1H. Further, the judgment can be made in the HUD area AH. For example, the area 1Ha shown in the example of fig. 3 may also coincide with the HUD area AH.

The laminated glass 1 of the present embodiment displays a HUD image by reflecting light from a projector by the reflection layer 16. The inventors have found that a thicker PVB layer 20 between the reflective layer 16 and the second glass substrate 14 can result in a reduced visibility of the HUD image known as orange peel. In contrast, in the laminated glass 1 of the present embodiment, the thickness D5 of the PVB layer 20 is reduced to 25 μm or less, whereby orange peel can be suppressed to suppress a decline in HUD image visibility, and the thickness D5 is reduced to 2 μm or more to ensure adhesion of the PVB layer 20. In addition, since the bubble remaining rate of the laminated glass 1 of the present embodiment is 2% or less, the deterioration of the visibility of the glass can be suppressed. Further, in the double-curved laminated glass bent in the X-direction and the Y-direction, bubbles are less likely to fall off and remain when the members are laminated. In contrast, in the laminated glass 1 of the present embodiment, by providing the PVB layer 20, bubbles can be removed appropriately at the time of lamination, and the bubble remaining rate can be reduced.

(method for producing PVB layer)

Next, a method for manufacturing the laminated glass 1 described above will be described. Fig. 4 is an illustration of a method of making a PVB layer. In the present manufacturing method, as shown in fig. 4, a substrate B2 for forming provided on a substrate B1 is prepared. The forming substrate B2 has irregularities (embossments) formed on a surface B2a opposite to the substrate B1. In the present manufacturing method, as shown in step S10 of fig. 4, the coating liquid 20A is applied to the surface B2a of the formation substrate B2. The coating liquid 20A is a liquid obtained by adding a PVB resin as a solid PVB layer 20 material to ethanol as a solvent (solvent). The PVB resin added to the coating liquid 20A is preferably added in an amount of 6% to 15% by mass relative to the total amount of the coating liquid 20A. The solvent is not limited to ethanol, and may be any liquid. In addition, a silane additive may be added to the coating liquid 20A as an additive. The amount of the coating liquid 20A applied to the formation substrate B2 is set so that the thickness D5 of the PVB layer 20 when laminated on the laminated glass 1 is within the above-mentioned numerical range.

After the coating liquid 20A is applied to the surface B2a of the forming substrate B2, the liquid component of the coating liquid 20A is removed by drying as shown in step S12 of fig. 4, and the PVB layer 20 before being laminated on the laminated glass 1 is formed. The PVB layer 20 before lamination has irregularities (embossments) formed on one surface 20a in contact with the surface B2a of the forming substrate B2. The surface 20b of the PVB layer 20 before lamination on the opposite side to the surface 20a may not have any irregularities, and may have any shape.

Fig. 5 is a schematic diagram showing PVB layers prior to lamination. As shown in fig. 5, the thickness D5a is the thickness of the PVB layer 20 before lamination. Thickness D5a refers to the thickness of the thickest portion of PVB layer 20 prior to lamination, in other words, refers to the Z-direction length between the protruding portion on surface 20a at the location furthest from surface 20b and the protruding portion on surface 20b at the location furthest from surface 20 a. In this case, the thickness D5a is 30 μm or less, preferably 25 μm or less, and more preferably 10 μm or less. The thickness D5a is 6.2 μm or more, preferably 6.4 μm or more, and more preferably 6.6 μm or more. When the thickness D5a is within this numerical range, the thickness D5 after lamination can be within the above numerical range, and the adhesion can be ensured while suppressing the deterioration of the visibility of the HUD image.

As shown in fig. 5, the thickness (height) of the portion of the PVB layer 20 before lamination where the irregularities are formed is referred to as a thickness D6a. Thickness D6a refers to the Z-direction length between the protruding portion on surface 20a of PVB layer 20 before lamination at the location furthest from surface 20b and the portion on surface 20a of PVB layer 20 before lamination at the location closest to surface 20 b. That is, the thickness D6a can be said to be the maximum height (maximum height roughness) Rz of the surface 20a specified by JIS B0601. In this case, the thickness D6a is 5 μm or more, more preferably 5.4 μm or more. In addition, thickness D6a is preferably thinner than thickness D5 of PVB layer 20 prior to lamination. The thickness D5a within this numerical range can form irregularities appropriately, remove bubbles appropriately at the time of lamination, and reduce the bubble remaining rate of the laminated glass 1. The thicknesses D5a and D6a can be said to be thicknesses of the PVB layer 20 before lamination in a state where no pressure higher than atmospheric pressure is applied.

The ratio of the thickness D6a to the thickness D5a is a thickness ratio. In this case, the thickness ratio is less than 0.95, more preferably 0.82 or less, and still more preferably 0.63 or less. The thickness ratio is preferably 0.18 or more, more preferably 0.22 or more, and even more preferably 0.27 or more. When the thickness ratio is within this range, the PVB layer 20 can be thinned in consideration of deterioration of image clarity, and the thickness of the non-uneven portion can be ensured to suppress breakage of the PVB layer before lamination.

The arithmetic average roughness Ra of the surface 20a of the PVB layer 20 before lamination is preferably 0.1 μm or more and 10 μm or less, more preferably 0.5 μm or more and 10 μm or less, and still more preferably 0.5 μm or more and 5 μm or less, which is defined in JIS B0601. When Ra is within this range, irregularities can be formed over the entire surface 20a, and the bubble remaining rate of the laminated glass 1 can be reduced. That is, the surface 20a of the PVB layer 20 has an arithmetic average roughness Ra of 0.1 μm or more and 10 μm or less, and thus can maintain air permeability and suppress the occurrence of irregularities after press-bonding to a glass substrate.

The shape and size of the irregularities on the surface 20a of the PVB layer 20 before lamination are similar to those of the irregularities on the surface B2a of the forming substrate B2. Therefore, the thicknesses D5a and D6a of the PVB layer 20 before lamination and the surface roughness of the surface 20a described above depend on and depend on the shape and size of the surface B2a of the formation substrate B2.

(method for producing laminated glass)

Next, a method for manufacturing the laminated glass 1 using the PVB layer 20 manufactured by the above method will be described. Fig. 6 is an explanatory diagram of a method for manufacturing a laminated glass. In the present manufacturing method, the PVB layer 20, the reflection layer 16, the first glass substrate 12, the second glass substrate 14, and the interlayer 18 manufactured as described above are laminated to manufacture the laminated glass 1. Specifically, as shown in step S6 of fig. 6, the surface 16a of the reflective layer 16 is brought into contact with the surface 20B of the pre-lamination PVB layer 20 formed on the surface B2a of the formation substrate B2, and the surface 20B is bonded to the surface 16 a. Thereby, the reflective layer 16 and the PVB layer 20 are bonded and laminated. In bonding the reflecting layer 16 and the PVB layer 20, for example, a pressure bonding treatment is performed by heating and pressurizing the reflecting layer 16 and the PVB layer 20 at a temperature of 80 ℃ or higher, preferably 100 ℃ or higher and 150 ℃ or lower, preferably 130 ℃ or lower and a pressure of 0.6MPa or higher, preferably 1.0MPa or higher and 3.0MPa or lower, preferably 1.5MPa or lower.

Next, as shown in step S22 of fig. 6, the formation substrate B2 is removed from the PVB layer 20 laminated on the reflection layer 16. Thereby, the surface 20a of the PVB layer 20 on which the irregularities are formed is exposed. Any method can be used for removing the formation substrate B2 from the PVB layer 20.

Subsequently, as shown in step S24 of fig. 6, the laminate of the reflective layer 16 and the PVB layer 20, the first glass substrate 12, the second glass substrate 14, and the interlayer 18 are laminated. The surface 18a and the surface 18b of the intermediate layer 18 are formed with irregularities. The shape and size of the embossments of surface 18a and surface 18b can be any, for example, the same shape and size as surface 20a of PVB layer 20. In the lamination, the surface 18a of the intermediate layer 18 is brought into contact with the surface 16b of the reflective layer 16 on the opposite side of the surface 16a, and the surface 18a is bonded to the surface 16 b. The pressure and temperature conditions used to bond surface 18a and surface 16b may be the same as those used to bond reflective layer 16 and PVB layer 20. Further, the surface 18b of the intermediate layer 18 opposite to the surface 18a is brought into contact with the surface 12a of the vehicle interior side of the first glass substrate 12, and the surface 18b is bonded to the surface 12 a. Further, the surface 14b of the second glass substrate 14 on the opposite side of the vehicle side from the surface 14a is brought into contact with the surface 20a of the PVB layer 20, and the surface 14b is bonded to the surface 20 a. Thereby, the laminate of the reflective layer 16 and the PVB layer 20, the first glass substrate 12, the second glass substrate 14, and the interlayer 18 are laminated. Specifically, a glass laminate is formed by sandwiching a laminate of the interlayer 18, the reflective layer 16, and the PVB layer 20 between the first glass substrate 12 and the second glass substrate 14. Then, the glass laminate is placed in a rubber bag, and bonded at a temperature of about 70 ℃ to 130 ℃ under a vacuum of-65 kPa to-100 kPa. Further, for example, the pressure-bonding treatment may be performed under heating and pressurizing conditions under a pressure of 0.6MPa to 1.5MPa and a temperature of 100 ℃ to 150 ℃. In step S24, the first glass substrate 12 and the second glass substrate 14 each having a flat plate shape may be subjected to bending, and a laminate of the interlayer 18, the reflective layer 16, and the PVB layer 20 may be laminated between the first glass substrate 12 and the second glass substrate 14 after the bending. Further, a PVB layer 20 may be added, and the PVB layer 20 may be laminated between the second glass substrate 14 and the laminate of the reflective layer 16 and the PVB layer 20. By stacking a plurality of PVB layers 20, adjustment of the film thickness becomes easy.

In this way, in step S24, after forming the laminate of the interlayer 18, the reflection layer 16, and the PVB layer 20, the laminate is sandwiched between the first glass substrate 12 and the second glass substrate 14, and then laminated. However, the order of stacking the components and the conditions of stacking in step S24 are not limited to the above description, and may be any.

By stacking the components in step S24, the laminated glass 1 can be produced as shown in step S26. In the case where the light shielding layer 22 is provided, the light shielding layer 22 may be formed, and other layers may be laminated as necessary.

As described above, in the manufacturing method of the present embodiment, since the surface 20a is roughened while thinning the PVB layer 20 before lamination, not only adhesion can be ensured while suppressing a decrease in visibility of the HUD image, but also the bubble remaining rate of the laminated glass 1 can be reduced.

(effects of the present embodiment)

As described above, the laminated glass 1 of the present embodiment includes: a first glass substrate 12, a second glass substrate 14, a reflective layer 16 disposed between the first glass substrate 12 and the second glass substrate 14, and a PVB layer 20 disposed between the second glass substrate 14 and the reflective layer 16 and formed of a polyvinyl butyral resin. In the laminated glass 1, the thickness D5 of the PVB layer 20 is 2 μm or more and 25 μm or less, the radius of curvature in the Y direction (longitudinal direction) is 20000mm or less, the radius of curvature in the X direction (transverse direction) is 10000mm or less, and the bubble remaining rate is 2% or less. In the laminated glass 1 of the present embodiment, the thickness D5 of the PVB layer 20 is reduced to 25 μm or less, whereby orange peel can be suppressed to suppress a decline in HUD image visibility, and the thickness D5 is 2 μm or more to ensure adhesion of the PVB layer 20. Further, the laminated glass 1 of the present embodiment has a bubble remaining rate of 2% or less, and therefore can suppress a decrease in visibility of the glass. Further, in the double-curved laminated glass bent in the X-direction and the Y-direction, bubbles are not easily removed and bubbles are easily left when the members are laminated. In contrast, in the laminated glass 1 of the present embodiment, by providing the PVB layer 20, bubbles can be removed appropriately at the time of lamination, and the bubble remaining rate can be reduced. The laminated glass 1 is preferably manufactured by the manufacturing method described above, but is not limited to the manufacturing method described above, and may be manufactured by any method.

The laminated glass 1 preferably further includes an intermediate layer 18 formed of a polyvinyl butyral resin and provided between the first glass substrate 12 and the reflection layer 16. The thickness of the interlayer 18 is thicker than the PVB layer 20. The laminated glass 1 of the present embodiment can maintain strength appropriately by providing the interlayer 18 thicker than the PVB layer 20.

In the laminated glass 1, the thickness D5 of the PVB layer 20 is preferably 4 μm or more and 25 μm or less, and more preferably the thickness D5 of the PVB layer 20 is 4 μm or more and 20 μm or less. This can suitably suppress a decrease in visibility of the HUD image.

The laminated glass 1 preferably has a length in the X direction and the Y direction of 200mm or more. In the laminated glass 1 having such a large size that bubbles are hardly removed, the inclusion of the PVB layer 20 can reduce the bubble remaining rate.

The method for producing the PVB layer according to the present embodiment includes: a step of applying a coating liquid 20A obtained by adding a polyvinyl butyral resin to a liquid to a surface B2a of a substrate (substrate B2 for forming) having irregularities formed on the surface B2a, and a step of forming a PVB layer 20 of a polyvinyl butyral resin having a thickness D5a of 30 [ mu ] m or less, a maximum height Rz (thickness D6 a) of 5 [ mu ] m or more, and a ratio (thickness ratio) of the maximum height Rz (thickness D6 a) to the thickness D5a of less than 0.95 by drying the coating liquid 20A. According to the present manufacturing method, the thickness D5a is set to 30 μm or less, whereby the thickness of the PVB layer 20 after lamination can be reduced, and a reduction in visibility of the HUD image can be suppressed. Further, by setting the maximum height Rz to 5 μm or more, appropriate irregularities can be formed on the surface 20a, and the bubble remaining rate can be reduced. Further, by making the thickness ratio smaller than 0.95, the thickness of the portion where the irregularities are not formed can be ensured, and the strength of the PVB layer 20 can be maintained.

In the step of forming the PVB layer 20, it is preferable to form the PVB layer 20 having a thickness D5a of 25 μm or less. By setting the thickness D5a to this range, the reduction in visibility of the HUD image can be suitably suppressed.

In the step of forming the PVB layer 20, it is preferable to form the PVB layer 20 having a maximum height Rz of 5.4 μm or more. By setting the maximum height Rz to this range, the bubble remaining rate can be reduced.

In the step of forming the PVB layer 20, the PVB layer 20 is preferably formed at a ratio (thickness ratio) of 0.82 or less. By setting the thickness ratio to this range, the strength of the PVB layer 20 can be maintained.

The method for producing the laminated glass 1 according to the present embodiment is to laminate the PVB layer 20, the reflection layer 16, the first glass substrate 12, and the second glass substrate 14 produced by the above-described method to produce the laminated glass 1. According to the present manufacturing method, the reduction in visibility of the HUD image can be suppressed, the bubble remaining rate can be reduced, and the strength of the PVB layer 20 can be maintained.

The method for producing the laminated glass 1 includes: a step of adhering a surface 20B of the PVB layer 20 on the opposite side from the base material (the forming substrate B2) to the reflective layer 16, a step of removing the base material from adhering to the reflective layer PVB layer, a step of adhering the second glass base 14 to a surface 20a of the PVB layer 20 on the opposite side from the reflective layer 16, and a step of laminating the first glass base 12 on a surface 16B of the reflective layer 16 on the opposite side from the PVB layer 20. According to the present manufacturing method, the reduction in visibility of the HUD image can be suppressed, the bubble remaining rate can be reduced, and the strength of the PVB layer 20 can be maintained.

Example (example)

The following examples are given. In examples 1 to 11, the material of the adhesive layer, the thickness of the adhesive layer after lamination, the glass dimensions (length) in the longitudinal and transverse directions, the glass radius of curvature in the longitudinal and transverse directions, and the bubble remaining rate were varied to evaluate the visibility and image clarity of the bubble. The adhesive layer is a layer corresponding to the PVB layer 20 of the present embodiment. All examples are common to the layers other than the adhesive layer. The laminated glass is formed by laminating a first glass substrate, an intermediate layer, a reflecting layer, an adhesive layer, and a second glass substrate in this order, and is formed by embossing a glass plate having a thickness of 2.0mm and an intermediate layer having a thickness of 0.76mm, whereby no bubbles remain in the intermediate layer. The bubble remaining rate is a ratio of the area of the bubble present in the 100mm square region where the bubble remains most on the entire laminated glass to the area of the region, and is the bubble remaining rate.

The visibility concerning the bubbles was marked as "o" when the bubble remaining rate was 2% or less, and as "x" when the bubble remaining rate was more than 2%.

The image clarity was evaluated as to whether or not "the longitudinal strain amount of the line" exceeded 0.017deg when a transverse line of a width of 0.034deg (=2 min) was projected away from the laminated glass 2m, "the longitudinal strain amount of the line" was marked as o when not exceeding 0.017deg (=1 min) and as x when exceeding 0.017deg (=1 min).

Example 1

The laminated glass of example 1 was produced by using PVB as the adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 2. Mu.m, the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and the bubble remaining rate was 1%. For example, the bubble remaining rate may be 2% or less by embossing (embossing) the surface of the adhesive layer before lamination, but the method of making the bubble remaining rate 2% or less is not limited to embossing, and may be performed by any method. That is, in example 1 and examples 2 to 6 described later, the bubble remaining rate was suppressed to be low by performing the embossing process, but the method of suppressing the bubble remaining rate to be low is not limited to the embossing process.

Example 2

The laminated glass of example 2 was manufactured by using PVB as an adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 4. Mu.m, and the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and a sample having a bubble remaining rate of 0% was obtained.

Example 3

The laminated glass of example 3 was manufactured by using PVB as an adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 8. Mu.m, and the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and a sample having a bubble remaining rate of 0% was obtained.

Example 4

The laminated glass of example 4 was produced by using PVB as an adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 20. Mu.m, the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and the bubble remaining rate was 0%.

Example 5

The laminated glass of example 5 was manufactured by using PVB as an adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 25. Mu.m, and the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and a sample having a bubble remaining rate of 0% was obtained.

Example 6

The laminated glass of example 6 was produced by using PVB as the adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 30. Mu.m, the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and the bubble remaining rate was 0%.

Example 7

The laminated glass of example 7 was manufactured by using PVB as an adhesive layer, and the laminated adhesive layer was 25 μm thick, and the surface of the adhesive layer was not embossed (i.e., concave-convex), and the laminated glass had a longitudinal length of 1200mm and a transverse length of 1600mm, and had a longitudinal radius of curvature of 20000mm and a transverse radius of curvature of 10000mm, whereby a sample having a bubble remaining rate of 6% was obtained.

Example 8

The laminated glass of example 8 was produced by using a UV curable resin as an adhesive layer, and the laminated adhesive layer was made to have a thickness of 2 μm, and embossing (embossing) was not performed on the surface of the adhesive layer, so that the laminated glass had a longitudinal length of 200mm and a transverse length of 200mm, and the laminated glass had a longitudinal radius of curvature of 20000mm and a transverse radius of curvature of 10000mm, whereby a sample having a bubble remaining rate of 5% was produced. The UV-curable resin here was specifically a mixture of 100 parts of A-TMPT (New Zhongcun chemical Co., ltd.) and 5 parts of Omnirad184 (IGM. Resins. B.V.). The same applies to the UV curable resin in the following examples.

Example 9

The laminated glass of example 9 was produced by using a UV curable resin as an adhesive layer, and the laminated adhesive layer was made to have a thickness of 2 μm, and embossing (embossing) was not performed on the surface of the adhesive layer, so that the laminated glass had a longitudinal length of 1200mm and a transverse length of 1600mm, and the laminated glass had a longitudinal radius of curvature of 20000mm and a transverse radius of curvature of 10000mm, whereby a sample having a bubble remaining rate of 6% was produced.

Example 10

The laminated glass of example 10 was produced by using a UV curable resin as an adhesive layer, and the laminated adhesive layer was 20 μm thick, and embossing (embossing) was not performed on the surface of the adhesive layer, and the laminated glass was made to have a longitudinal length of 1200mm, a transverse length of 1600mm, a longitudinal radius of curvature of 20000mm, a transverse radius of curvature of 10000mm, and a bubble remaining rate of 6%.

Example 11

The laminated glass of example 11 was manufactured by using a UV curable resin as an adhesive layer, embossing (embossing) the surface of the adhesive layer so that the thickness of the laminated adhesive layer was 4 μm, and the longitudinal length of the laminated glass was 1200mm, the transverse length was 1600mm, the longitudinal radius of curvature of the laminated glass was 20000mm, the transverse radius of curvature was 10000mm, and a sample having a bubble remaining rate of 6% was obtained.

(evaluation results)

Table 1 shows the conditions and evaluation results of examples 1 to 11. Examples 1 to 5 correspond to examples and examples 6 to 11 correspond to comparative examples. As is clear from examples 1 to 5, the reduction in the residual rate of bubbles can be suppressed by setting the thickness of the adhesive layer made of PVB to 2 μm or more and 25 μm or less, and the reduction in visibility and image clarity due to bubbles can be suppressed. On the other hand, when the thickness of the adhesive layer is set to 2 μm, the adhesive layer breaks and cannot be formed properly. In examples 8 to 10, the bubble remaining rate was more than 2%, and therefore, the visibility due to the bubbles was lowered. Furthermore, UV curable resins are disadvantageous in terms of impact resistance compared to PVB. Further, as shown in example 11, when embossing was performed on the UV-curable resin, the adhesion of the adhesive layer to glass was deteriorated, and the image clarity could not be measured.

TABLE 1

Examples 12 to 23 were evaluated for image clarity, bubble remaining rate, and manufacturability by making the material of the adhesive layer, the thickness of the adhesive layer before lamination, the maximum height Rz of the adhesive layer before lamination (corresponding to thickness D6a in the embodiment), and Rz/adhesive layer thickness (corresponding to thickness ratio in the embodiment) different. In each example, 100 sheets of adhesive layers were formed, and 1 sheet, which did not break during the forming and did not have pattern fall off, was used to produce laminated glasses in the same manner as in examples 1 to 11. The evaluation of the image clarity was the same as in examples 1 to 11. The bubble remaining rate is a ratio of the area of the bubble present in the 100mm square region where the bubble remains most on the entire laminated glass to the area of the region, and is the bubble remaining rate. In the evaluation of the bubble remaining rate, 0% or less was marked with "o", 2% or less was marked with "Δ", and more than 2% was marked with "x", and the results were qualified as "o" and "Δ". Regarding manufacturability, the presence or absence of breakage of the adhesive layer at the time of molding and pattern release of the adhesive layer were evaluated, and it was evaluated that no breakage or pattern release was marked as "O" for 2 or less of 100 pieces, and that a mark of 3 to 4 pieces was marked as "delta", and that breakage or release was marked as "X" for 5 or more pieces, and that a mark was qualified. The pattern separation is a portion where the convex portions of the irregularities are broken (for example, the thickness is 80% or less compared to the adjacent convex portions) when the adhesive layer is peeled off from the forming substrate B2 as in step S22 of fig. 6. In addition, as an alternative evaluation, the breaking strength was evaluated using a single film of PVB and EVA as the material of the adhesive layer. The breaking strength was evaluated by using a dumbbell-shaped test piece having a distance (GL) between standard lines of 50mm prepared from a film of PVB and EVA in accordance with JIS K7161. The "evaluation result" indicates that the evaluation was impossible (including non-evaluation).

Example 12

The laminated glass of example 12 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 6.2. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5. Mu.m, and the Rz/adhesive layer thickness was 0.8.

Example 13

The laminated glass of example 13 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 6.6. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.82.

Example 14

The laminated glass of example 14 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 8.6. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.63.

Example 15

The laminated glass of example 15 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 9.8. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.55.

Example 16

The laminated glass of example 16 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 25. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.22.

Example 17

The laminated glass of example 17 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 30. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.18.

Example 18

The laminated glass of example 18 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 35. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.16.

Example 19

The laminated glass of example 19 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 5.7. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.95.

Example 20

The laminated glass of example 20 used PVB as the adhesive layer, the thickness of the adhesive layer before lamination was 9.8. Mu.m, the maximum height Rz of the adhesive layer before lamination was 4. Mu.m, and the Rz/adhesive layer thickness was 0.41.

Example 21

The laminated glass of example 21 used EVA (Ethylene Vinyl Acetate Copolymer; ethylene-vinyl acetate copolymer) as the adhesive layer, the thickness of the adhesive layer before lamination was 6.2. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5. Mu.m, and the Rz/adhesive layer thickness was 0.8.

Example 22

The laminated glass of example 22 used EVA as the adhesive layer, the thickness of the adhesive layer before lamination was 6.6. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.82.

Example 23

Example 23 laminated glass was laminated using EVA as the adhesive layer, the thickness of the adhesive layer before lamination was 35. Mu.m, the maximum height Rz of the adhesive layer before lamination was 5.4. Mu.m, and the Rz/adhesive layer thickness was 0.16.

(evaluation results)

Table 2 shows the conditions and evaluation results of examples 12 to 23. Examples 12 to 17 correspond to examples and examples 18 to 23 correspond to comparative examples. As is clear from examples 12 to 17 and 19, the thickness of the adhesive layer before lamination made of PVB was 30 μm or less, and the decrease in image clarity was suppressed. In addition, as shown in examples 12 to 18, it is clear that manufacturability can be maintained by making the Rz/adhesive layer thickness smaller than 0.95. In example 20, the bubble remaining rate was more than 2%. That is, as shown in example 20, the Rz value was less than 5. Mu.m, and the bubble remaining rate was not acceptable. In example 20, the appearance was poor due to bubbles, and the image clarity could not be evaluated. It is also clear from examples 21 to 23 that at least one of manufacturability and sharpness of image was not satisfactory by making the adhesive layer EVA. Regarding the evaluation of breaking strength, PVB film was 399 mpa, eva film was 190mpa, and the breaking strength of eva was low, so that the manufacturability was deteriorated. The adhesive layer preferably has a breaking strength of 300MPa or more such as PVB.

TABLE 2

The embodiments of the present invention have been described above, but the embodiments are not limited to the content of the embodiments. The above-described constituent elements include elements which can be easily conceived by those skilled in the art, substantially the same elements, and elements within a so-called equivalent range. The above components may be appropriately combined. Further, various omissions, substitutions, and changes in the constituent elements may be made without departing from the spirit of the embodiments described above.

Symbol description

1 laminated glass

12 first glass substrate

14 second glass substrate

16 reflective layer

18 intermediate layer

20PVB layer.

Claims

1. A laminated glass, comprising:

a first glass substrate,

A second glass substrate,

A reflective layer disposed between the first glass substrate and the second glass substrate

A PVB layer formed of a polyvinyl butyral resin and disposed between the second glass substrate and the reflective layer,

wherein the PVB layer has a thickness of 2 μm to 25 μm,

the radius of curvature of the laminated glass in the longitudinal direction is 20000mm or less, the radius of curvature of the laminated glass in the transverse direction is 10000mm or less,

the bubble remaining rate of the laminated glass is 2% or less.

2. The laminated glass according to claim 1, further comprising an intermediate layer formed of a polyvinyl butyral resin and provided between the first glass substrate and the reflecting layer,

the thickness of the interlayer is thicker than the PVB.

3. The laminated glass of claim 1 or 2, wherein the PVB layer has a thickness of from 4 μm to 25 μm.

4. The laminated glass of claim 3, wherein the PVB layer has a thickness of from 4 μm to 20 μm.

5. The laminated glass according to any one of claims 1 to 4, wherein the diameter of the bubbles of the laminated glass in relation to the bubble remaining ratio is 2mm or less.

6. A laminated glass as claimed in any one of claims 1 to 5, wherein the longitudinal and transverse lengths are 200mm or more.

7. A method of making a PVB layer comprising: a step of applying a coating liquid obtained by adding a polyvinyl butyral resin to a liquid to the surface of a substrate having irregularities formed on the surface, and

and a step of forming a PVB layer, which is a layer of the polyvinyl butyral resin, having a thickness of 30 [ mu ] m or less, a maximum height Rz of the substrate-side surface of 5 [ mu ] m or more, and a ratio of the maximum height Rz to the thickness of less than 0.95 by drying the coating liquid.

8. The method of claim 7, wherein in the step of forming the PVB layer, the PVB layer having the thickness of 25 μm or less is formed.

9. The method of claim 7 or 8, wherein in the step of forming the PVB layer, the PVB layer having the maximum height Rz of 5.4 μm or more is formed.

10. The method of making a PVB layer of any one of claims 7-9 wherein, in the step of forming the PVB layer, the PVB layer is formed at the ratio of 0.82 or less.

11. A method of manufacturing laminated glass, wherein the PVB layer, the reflective layer, the first glass substrate, and the second glass substrate manufactured by the method of manufacturing a PVB layer according to any one of claims 7 to 10 are laminated to manufacture laminated glass.

12. The method for producing a laminated glass according to claim 11, comprising:

a step of adhering a surface of the PVB layer opposite to the base material to the reflecting layer,

a step of removing the substrate from the PVB layer adhered to the reflective layer,

a step of bonding the second glass substrate to a surface of the PVB layer opposite to the reflective layer, and

and laminating the first glass substrate on a surface of the reflective layer opposite to the PVB layer.