JP7620438B2 - Vehicle window glass - Google Patents

Description

This disclosure relates to vehicle window glass.

In recent years, with the demand for lighter vehicles such as automobiles and railway cars, there is a demand for lighter laminated glass to be used in vehicle windows. Thus, efforts are being made to reduce the weight of laminated glass by making the glass sheets used in the laminated glass thinner.

Lightweight laminated glass with different thicknesses is often used for vehicle window glass, with the glass sheet on the outside of the vehicle being thicker to increase resistance to small flying debris while the vehicle is moving, and the glass sheet on the inside of the vehicle being thinner to reduce weight.

Patent Document 1 discloses laminated glass having glass sheets with different thicknesses and a multilayer interlayer made of polyvinyl butyral (PVB) layers.

Patent document 2 also discloses laminated glass in which a chemically strengthened glass sheet is used for the outer glass sheet, and the thickness of the outer glass sheet is made thinner than that of the inner glass sheet.

Special Publication No. 2015-516934 Patent No. 5890518

One of the performance requirements for vehicle window glass is chipping resistance. Chip resistance is an index showing how difficult it is to chip or break when a small flying object strikes the vehicle window glass while the vehicle is traveling. The inventors' research has revealed that when an interlayer film with a relatively low Young's modulus is used, reducing the thickness of the exterior glass sheet to reduce weight not only reduces the rigidity of the laminated glass, but also reduces chipping resistance and makes the glass more susceptible to breaking. In addition, in order to improve the strength of lightweight laminated glass, tempered glass is sometimes used for the exterior glass sheet, but in this case, it has been found that chipping resistance is further reduced due to tensile stress generated inside the glass.

In view of the above, the objective of this disclosure is to provide a lightweight vehicle window glass that has excellent rigidity and chipping resistance.

The problem of the present disclosure is solved by the following configuration.
＜1＞
A first glass plate having an S1 surface facing the outside of a vehicle and an S2 surface opposite to the S1 surface;
A second glass plate having an S4 surface facing the interior side of the vehicle and an S3 surface opposite to the S4 surface;
an interlayer film including at least one layer disposed between the first glass plate and the second glass plate and facing the S2 surface and the S3 surface;
A vehicle window glass comprising:
The Young's modulus of all layers constituting the intermediate film is 2.5 MPa to 200 MPa at 23° C.
MPa,
The first glass sheet is not tempered,
The first glass plate has a thickness of 1.5 mm or less.
＜2＞
The vehicle window glass according to <1>, wherein the first glass plate has a thickness of 0.3 mm to 1.5 mm.
＜3＞
The vehicle window glass according to <1> or <2>, wherein the Young's modulus of all layers constituting the interlayer film is 10 MPa to 100 MPa at 23° C.
＜4＞
The vehicle window glass according to any one of <1> to <3>, wherein the second glass plate has a thickness of 0.3 mm to 1.7 mm.
＜5＞
The vehicle window glass according to any one of <1> to <4>, wherein the interlayer film is an interlayer film constituted by one layer.

This disclosure makes it possible to provide lightweight vehicle window glass with excellent rigidity and chipping resistance.

1 is a schematic cross-sectional view of an example of a vehicle window glass. 1 is a schematic cross-sectional view of an example of a vehicle window glass. FIG. 2 is a schematic diagram for explaining a chipping resistance test. FIG. 1 is a schematic diagram for explaining a concentric bending test.

The vehicle window glass of the present disclosure includes a first glass plate having an S1 surface facing the outside of the vehicle and an S2 surface opposite to the S1 surface;
A second glass plate having an S4 surface facing the interior side of the vehicle and an S3 surface opposite to the S4 surface;
an interlayer film including at least one layer disposed between the first glass plate and the second glass plate and facing the S2 surface and the S3 surface;
A vehicle window glass comprising:
The Young's modulus of all layers constituting the intermediate film is 2.5 MPa to 200 MPa at 23° C.
MPa,
The first glass sheet is not tempered;
The first glass plate has a thickness of 1.5 mm or less.

Figure 1 shows a schematic cross-sectional view of an example of a vehicle window glass according to the present disclosure.

The vehicle window glass 10 in FIG. 1 has a first glass plate 1, a second glass plate 2, and an interlayer film 3. The first glass plate 1 has an S1 surface facing the outside of the vehicle and an S2 surface opposite the S1 surface. The second glass plate 2 has an S4 surface facing the interior of the vehicle and an S3 surface opposite the S4 surface. The interlayer film 3 is disposed between the first glass plate 1 and the second glass plate 2 so as to face the S2 surface and the S3 surface. The interlayer film 3 is an interlayer film composed of one layer (a single-layer interlayer film).

Figure 2 shows a schematic cross-sectional view of another example of a vehicle window glass according to the present disclosure.

The vehicle window glass 11 in FIG. 2 is similar to the vehicle window glass 10 in FIG. 1, except that instead of the single-layer interlayer film 3 in FIG. 1, it has a three-layer interlayer film 4 made up of layers 4A to 4C that make up the interlayer film.

The vehicle window glass of the present disclosure is preferably made of lightweight laminated glass.

The mass per ^m2 of the vehicle window glass is preferably 3 kg to 9 kg, and more preferably 4 kg to 8 kg.
[Interlayer film]
The interlayer film is composed of at least one layer, i.e., the interlayer film may have a single layer structure or a multi-layer structure.

The Young's modulus of all layers constituting the interlayer is 2.5 MPa to 200 MPa at 23°C, preferably 10 MPa to 100 MPa, more preferably 20 MPa to 100 MPa, and particularly preferably 30 MPa to 75 MPa. When the Young's modulus of all layers constituting the interlayer is 2.5 MPa to 200 MPa at 23°C, the bending rigidity of the laminated glass using this film can be increased.

The overall bending rigidity of laminated glass is correlated with the thickness of the glass sheets that make up the laminated glass and the Young's modulus of the interlayer film. Therefore, vehicle window glass that includes an interlayer film with a low Young's modulus, such as the sound-insulating interlayer film used in conventional sound-insulating laminated glass, has a lower bending rigidity than glass that does not include an interlayer film with a low Young's modulus. Therefore, it is preferable for the interlayer film to have a higher Young's modulus, regardless of the number of layers.

In addition, if the interlayer is multi-layered, each layer may have different rigidity.

Details of the method for measuring the Young's modulus of interlayer film samples are shown below.

The Young's modulus of the interlayer film samples was measured in accordance with JIS K 7161-1. This method aims to determine the tensile modulus of elasticity (Young's modulus) of the test specimen by measuring the force and elongation applied to the test specimen when it is pulled at a constant speed along the main axis (length direction) until the stress or strain (elongation) reaches a predetermined value.

The test machine used was an A&D Tensilon universal testing machine (RTC-2410) that complies with JIS K 7161-1.

The test specimens were made by machining the interlayer film into a "tensile dumbbell shape of No. 5" conforming to JIS K 6251.

The gauge length of the test specimen was 33 mm.

The number of test pieces was one for each interlayer film.

The prepared test specimens were stored for more than 4 hours in an environment with a temperature of 23°C and a humidity of 40-60%.

The tensile tests were performed in the same environment as when the samples were stored: 23°C and 40-60% humidity.

The tensile test was performed without applying a preliminary force to the interlayer film sample.

The test speed during the tensile test was 0.33 mm/min, which is the speed that gives a strain of 1% of the gauge length per minute.

The stress σ [MPa] applied to the test piece was determined as the force F [N] applied during measurement divided by the initial cross-sectional area A [mm ² ] of the test piece.

The strain ε [-] generated in the test piece was determined as the value obtained by dividing the increase in the gauge length of the test piece, ΔL ₀ [mm], by the gauge length of the test piece, L ₀ [mm].

The Young's modulus E [MPa] of the test specimen was determined by dividing the difference between the stress σ ₂ [MPa] at the strain ε ₂ (0.25%) of the test specimen and the stress σ ₁ [MPa] at the strain ε ₁ (0.05%) of the test specimen by the difference between the strain ε ₂ of the test specimen and the strain ε ₁ of the test specimen.

The stress, Young's modulus, and strain in this test were reported to two significant figures.

The layers constituting the intermediate film can be made of, for example, polyvinyl butyral (PVB), SentryGlas® (Dupon), polycarbonate, ionomer, polyethylene terephthalate (PET), or other suitable polymer or thermoplastic material. In addition, it is preferable that the layers constituting the intermediate film are made of a thermoplastic resin.

From the viewpoint of simplifying the manufacturing method and reducing the weight of the vehicle window glass, it is preferable that the interlayer film is an interlayer film composed of one layer (a single-layer interlayer film).

The thickness of the interlayer is not particularly limited, but from the viewpoint of increasing the bending rigidity and penetration resistance of the laminated glass, it is preferably 0.3 mm to 3.0 mm, and more preferably 0.3 mm to 1.0 mm.

The method for producing the interlayer film in the present disclosure is not particularly limited, and any known method can be used. For example, the method for forming the interlayer film raw material resin into a film includes, but is not limited to, the usual extrusion method or calendar roll method.
[First glass plate]
The first glass sheet in the vehicle window glass of the present disclosure has not been subjected to a tempering treatment (i.e., is a non-tempered glass). Here, the tempering treatment refers to a treatment (including both physical tempering and chemical tempering) for increasing the strength by applying a compressive stress to the surface of the glass sheet.

When a tempered glass plate is used as the first glass plate (the glass plate on the outside of the vehicle) in a vehicle window glass, the chipping resistance is reduced due to the tensile stress generated inside the glass.

The first glass plate is not particularly limited as long as it has not been subjected to a tempering treatment, and any known glass used for vehicle window glass (e.g., soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, etc.) can be used.
In order to adjust the optical properties of the glass plate, a coloring component such as Fe2O3, CeO2, TiO2, CoO, Cr2O3, NiO, or Se may be contained in an amount of up to 5 mass %.

The thickness of the first glass plate is 1.5 mm or less, preferably 0.3 mm to 1.5 mm, and more preferably 0.4 mm to 1.2 mm.
[Second glass plate]
The second glass plate in the vehicle window glass of the present disclosure may be a glass plate that has not been subjected to a tempering treatment, or may be a glass plate that has been subjected to a tempering treatment. The second glass plate is not particularly limited, and may be a known glass (e.g., soda-lime glass, borosilicate glass, alkali-free glass, quartz glass, physically tempered glass, chemically tempered glass, etc.) used in vehicle window glasses.
In order to adjust the optical properties of the glass plate, a coloring component such as Fe2O3, CeO2, TiO2, CoO, Cr2O3, NiO, or Se may be contained in an amount of up to 5 mass %.

The thickness of the second glass plate is not particularly limited, but is preferably 0.3 mm to 1.7 mm, more preferably 0.55 mm to 1.5 mm, and even more preferably 0.7 mm to 1.4 mm.

The manufacturing method (molding method) of the first glass plate and the second glass plate is not particularly limited, and a known manufacturing method (for example, a float method) can be used.
[Functional Layer]
The vehicle window glass of the present disclosure may further include a functional layer between the first glass plate and the second glass plate.

The vehicle window glass of the present disclosure can be manufactured by known methods using the components described above.

Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.
<Preparation of Laminated Glass Samples>
Glass plates having the thicknesses shown in Table 1 below were used as the first glass plate or the second glass plate.

The interlayer film samples A1, A2, and A3 below were used as the interlayer film.

Interlayer film A1: A single-layer interlayer film (thickness 0.78 mm) made of PVB with a high Young's modulus. The Young's modulus at 23°C was 49 MPa.

Interlayer film A2: An interlayer film (thickness 0.85 mm) with a three-layer structure of a PVB layer having a low Young's modulus, a PVB layer having a low Young's modulus, and a PVB layer having a low Young's modulus. The Young's modulus of each of the PVB layers having a low Young's modulus at 23°C was 1.3 MPa.

Interlayer film A3: A three-layer interlayer film (thickness 0.86 mm) consisting of a PVB layer with a high Young's modulus, a PVB layer with a low Young's modulus, and a PVB layer with a high Young's modulus. At 23°C, the Young's modulus of the PVB layer with a high Young's modulus that constitutes interlayer film A3 was 49 MPa, and the Young's modulus of the PVB layer with a low Young's modulus was 1.1 MPa.

Ordinary laminated glass is produced by sandwiching one continuous interlayer film between two glass plates, but in the manufacturing method of laminated glass for vehicles using a laminated interlayer film such as interlayer film A3, one PVB layer with a low Young's modulus is sandwiched between two PVB layers with a high Young's modulus, and the laminated interlayer film is then sandwiched between two glass plates.

In this case, the interfaces between the layers that make up the interlayer film become inconspicuous as the layers are fused together when the laminated glass for vehicles is heated and pressurized in the autoclave, so the visibility of passengers is not obstructed.

Each interlayer sample was sandwiched between the first and second glass plates, placed in a rubber bag, and suctioned under reduced pressure to remove any air remaining between the components. The degassed laminate was then placed in an autoclave for preliminary bonding. At this time, the temperature was set to 90°C, the pressure to 0.25 MPa, and the temperature retention time to 30 minutes. Next, the autoclave temperature was set to 135°C, the pressure to 1.3 MPa, and the temperature retention time to 25 minutes to perform final bonding, and the above laminates were integrated to obtain laminated glass.

The laminated glass samples produced are shown in Table 1 below.

In all examples and comparative examples except Comparative Example 4 and Comparative Example 13, the first glass plate and the second glass plate were not subjected to a tempering treatment. Specifically, in all examples and comparative examples except Comparative Example 4 and Comparative Example 13, the first glass plate and the second glass plate were obtained by forming soda-lime glass by the float method. The first glass plate in Comparative Example 4 and Comparative Example 13 is a chemically tempered aluminosilicate glass, and has a compressive stress layer on the S1 surface side (compressive stress 799 MPa, thickness 43.3 μm) and the S2 surface side (compressive stress 806 MPa, thickness 43.3 μm). The value of the compressive stress of the chemically tempered glass and the thickness of the compressive stress layer were obtained using a surface stress meter (Orihara Manufacturing Co., Ltd., FSM-6000LE) that uses the optical waveguide effect as the observation principle.
<Chipping resistance test>
As shown in Fig. 3, a silicon rubber sheet 31 (thickness 3 mm) with an opening of 150 mm x 150 mm in the center of a size of 300 mm x 300 mm and a plywood 32 (thickness 15 mm) were stacked, a test piece (laminated glass sample) 10A as a test specimen was placed on the silicon rubber sheet 31, and a Vickers diamond indenter 21 was dropped from a height h to examine chipping resistance. In order to make the indenter collide vertically with the test piece, a guide tube made of hard polyvinyl chloride was used as necessary. The test conditions were as follows.

Test conditions: Size of test piece (laminated glass): 300 mm x 300 mm
Vickers diamond indenter: 8.5 g (M0-MINDV, Nanovea)
Test temperature: 23°C
Specifically, a Vickers diamond indenter was dropped freely onto the center of the first glass plate side of the laminated glass samples of the examples and comparative examples. The drop height h was started from 100 mm, and if the length of the radial cracks generated in the laminated glass sample was less than 10 mm, the drop position was changed, the drop height was increased by 100 mm each time, and the test was repeated. When the length of the radial cracks generated in the laminated glass sample exceeded 10 mm, it was defined as breakage, and the drop height of the Vickers diamond indenter at that time was recorded as the Break Height. For each example and comparative example, the test was performed 10 times to obtain the average value of the Break Height. Furthermore, the length of the cracks generated at the time of breakage (Break Length) was measured, and the average value was calculated.

The maximum drop height was 2000 mm. If the length of the radial crack was less than 10 mm even at a drop height of 2000 mm, the length of the crack at that point was recorded as the break length, and the break height was recorded as 2100 mm, and the average value was calculated.

The results are shown in Table 1 above.
<Concentric bending test (rigidity evaluation)>
A concentric bending test was carried out using the laminated glass samples of Examples 1 to 4 and Comparative Examples 5 to 12 having glass plates of the same thickness as the laminated glass samples. Specifically, as shown in Fig. 4, a load was gradually increased on a test piece (laminated glass sample) 10A using a support ring 13 and a load ring 14, and the amount of deflection against the load when it reached 500 N was measured. An Instron material testing machine (Model 8871) was used as the testing machine.
<Test conditions>
Size of test piece (laminated glass sample): 300 mm x 300 mm
Load ring: diameter 50 mm, radius of curvature 2.5 mm
Support ring: diameter 150 mm, radius of curvature 2.5 mm
Crosshead speed: 1 mm/min Load surface: first glass plate side Test temperature: 23° C.
The results are shown in Table 1 above.
<Mass per unit area>
The mass per ^m2 of the prepared laminated glass sample was measured.

The results are shown in Table 1 above.

The results shown in Table 1 show that the laminated glass samples of Examples 1 to 4 have a larger average break height and a smaller average break length than the laminated glass samples of Comparative Examples 1 to 13, and therefore have higher chipping resistance.

Comparative examples 1 to 3 used the same interlayer film A1 as in examples 1 to 4, but the thickness of the first glass plate exceeded 1.5 mm, and the chipping resistance was inferior to examples 1 to 4.

In Comparative Examples 5 to 8, the thickness of the first glass plate was 1.5 mm or less, as in Examples 1 to 4, but the Young's modulus at 23°C of all layers constituting the interlayer was less than 2.5 MPa, and the chipping resistance was inferior to Examples 1 to 4.

In Comparative Examples 9 to 12, the thickness of the first glass plate was 1.5 mm or less, as in Examples 1 to 4, but the Young's modulus at 23°C of some of the layers constituting the interlayer was less than 2.5 MPa, and the chipping resistance was inferior to Examples 1 to 4.

In Comparative Examples 4 and 13, the thickness of the first glass plate was 1.5 mm or less, as in Examples 1 to 4, and the same interlayer film A1 was used as in Examples 1 to 4. However, the first glass plate was tempered, and chipping resistance was significantly inferior to Examples 1 to 4. In Table 1, ">300" listed as the average break length for Comparative Examples 4 and 12 indicates that it exceeds 300 mm.

In addition, the laminated glass samples of Examples 1 to 4 showed smaller deflections when a constant load was applied in a concentric bending test than the laminated glass samples of Comparative Examples 5 to 12, which had glass plates of the same thickness, and were therefore superior in rigidity.

Furthermore, the laminated glass samples of Examples 1 to 4 had a mass per ^square meter of 4.8 to 6.2 kg, which indicated that they were lightweight.

From the above, it was found that the laminated glass samples of Examples 1 to 4 are lightweight and have excellent rigidity and chipping resistance, making them suitable for use as vehicle window glass.

REFERENCE SIGNS LIST 1 First glass plate 2 Second glass plate 3, 4 Interlayer 4A, 4B, 4C Layers constituting the interlayer S1 S1 surface S2 S2 surface S3 S3 surface S4 S4 surface 10, 11 Vehicle window glass 10A Laminated glass sample 13 Support ring 14 Load ring 21 Vickers diamond indenter h Drop height of Vickers diamond indenter 31 Silicone rubber sheet 32 Plywood

Claims (5)

A first glass plate having an S1 surface facing the outside of a vehicle and an S2 surface opposite to the S1 surface;
A second glass plate having an S4 surface facing the interior side of the vehicle and an S3 surface opposite to the S4 surface;
an interlayer film including at least one layer disposed between the first glass plate and the second glass plate and facing the S2 surface and the S3 surface;
A vehicle window glass comprising:
The intermediate film does not contain silica particles,
The Young's modulus of all layers constituting the interlayer is 10 MPa to 200 MPa at 23° C.,
The first glass plate and the second glass plate are not subjected to a tempering treatment,
The first glass plate has a thickness of 0.4 mm to 1.2 mm. The vehicle window glass according to claim 1, wherein the Young's modulus of all layers constituting the interlayer is 10 MPa to 100 MPa at 23°C. The vehicle window glass according to claim 1 or 2, wherein the thickness of the second glass sheet is 0.3 mm to 1.7 mm. The vehicle window glass according to any one of claims 1 to 3, wherein the interlayer film is an interlayer film composed of a single layer. A first glass plate having an S1 surface facing the outside of a vehicle and an S2 surface opposite to the S1 surface;
A second glass plate having an S4 surface facing the interior side of the vehicle and an S3 surface opposite to the S4 surface;
an interlayer film consisting of one layer, the interlayer film being disposed between the first glass plate and the second glass plate and facing the S2 surface and the S3 surface;
A vehicle window glass comprising:
The intermediate film does not contain silica particles,
The Young's modulus of the interlayer is 10 MPa to 50 MPa at 23° C.,
The first glass plate and the second glass plate are not subjected to a tempering treatment,
The first glass plate has a thickness of 0.4 to 1.2 mm;
The thickness of the second glass sheet is 0.7 mm to 1.4 mm.
Vehicle window glass.