JP2022081157A - Laminated glass - Google Patents

Abstract

To achieve a high adhesion strength and long-term reliability as a whole in a laminated glass even when one surface of a front glass and a rear glass has a weak strength compared to the other surface.SOLUTION: A front glass 2 and a rear glass 3 composing a laminated glass 1 are formed by folding a float glass so as to spread stripes formed on a float surface of the chemically strengthened float glass, and the float surface is adhered so as to face an opposite side to an attachment object. Even when a load from a user side is added to the float surface of the front glass, and tensile stress is generated on surfaces at opposite sides to the float surfaces of the front glass and the rear glass, the laminated glass is hardly broken due to that the other surfaces at the rear sides have a high strength compared to the float surface as the one surface at the front side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated glass in which two or more glass plates are laminated, and in particular, a laminated glass capable of exhibiting high strength as a whole even when one surface of each glass plate has a strong vulnerability. It is about.

The following Patent Document 1 discloses an invention of a windshield capable of preventing interference fringes from being generated even when an anti-fog sheet is attached. The present invention is a windshield of an automobile in which an information acquisition device that acquires information from outside the vehicle by irradiating and / or receiving light is arranged, and the information that the light passes through facing the information acquisition device. A laminated glass having an acquisition area and an anti-fog sheet in which at least an adhesive layer, a base film, and an anti-fog layer are laminated in this order, and at least the adhesive layer is attached to the inner surface of the vehicle in the information acquisition area. It is equipped with. The laminated glass contains at least one glass plate having two main surfaces having different tin oxide concentrations on the surface, and the inner surface of the vehicle is composed of a surface having a lower tin oxide concentration on the glass plate. There is.

The following Patent Document 2 discloses an invention of a laminated glass having improved visibility. The laminated glass of the present invention has a first glass plate whose thickness changes from one end to the opposite end and has lines formed in the horizontal direction, and a second glass having lines formed. It is located between the plate and the first glass plate and the second glass plate so that the streaks of the first glass plate and the streaks of the second glass plate are orthogonal to each other in the plate thickness direction. It is provided with an interlayer film for adhering the first glass plate and the second glass plate. The interlayer film has a first resin layer, a second resin layer, and a third resin layer, and the second resin layer is the first resin layer and the third resin layer. It is characterized in that it is located between and has a hardness lower than that of both the first resin layer and the third resin layer.

Japanese Unexamined Patent Publication No. 2020-73364 Japanese Unexamined Patent Publication No. 2018-158883

Display devices such as car navigation devices and speedometers of cars often have a cover on the outermost surface of the part exposed on the indoor side (that is, the user side who is the driver), but it is a high-class product. It tends to be preferred that the cover be made of glass in order to give a feeling and transparency. As such a glass cover, laminated glass in which the front glass / adhesive / back glass is arranged and bonded in this order from the user side toward the side where the display device is mounted may be used in order to prevent scattering. many.

When manufacturing such laminated glass, a groove-shaped streak is formed on the glass plate of the material by a carbide wheel or the like, which is a wheel-shaped rotary tool equipped with a blade made of a carbide material (hereinafter, this operation is referred to as "stripe". After that, the glass plates on both sides of the streaks are bent in the direction in which the streaks spread, and the glass plates are cut along the streaks to cut into the desired shape, which is used as the front glass and back glass. ing. Further, as the glass plate of the material used as the front glass and the back glass, glass manufactured by the float method for the purpose of cost reduction or the like (hereinafter, referred to as “float glass”) is often used, and this float is also used. Glass may be chemically strengthened and used, but the inventors of the present application recognize that in that case, there are problems as described in 1) to 3) below.

1) When a glass plate containing float glass is reinforced with a carbide wheel, microcracks and chips occur in and near the reinforced portion, making it easy to crack. For this reason, if the surface on the side with the lines (hereinafter referred to as the "lined surface") is attached to the display device toward the side where the display device is mounted, that is, the back side when viewed from the user (indoor side), the user side. When a load from the glass is applied to the surface opposite to the reinforced surface, tensile stress is generated on the reinforced surface, so that there is a problem that the glass is easily broken.

2) When the float glass is chemically strengthened, one surface of the float glass is difficult to be chemically strengthened. The float method is a method of manufacturing by flowing molten glass while floating it on a molten metal (Sn). Therefore, Sn is diffused from the surface in contact with the molten metal (Sn) (referred to as a “float surface” or a “bottom surface”) to the inside. Chemical strengthening is a method of increasing the strength by immersing the float glass in a molten salt such as potassium nitrate and replacing Na in the float glass with K in the molten salt having a larger ionic radius. However, even if chemical strengthening is performed, since Sn is diffused on the float surface, substitution by K is unlikely to occur, and the float surface is relatively compared to the other surface (this is referred to as “top surface”). The strength will be smaller. Therefore, when this float surface is attached to the display device toward the side where the display device is mounted, that is, the back side when viewed from the user (indoor side), the load from the user side is applied to the top surface on the opposite side to the float surface. In this case, tensile stress is generated on the float surface, so that there is a problem that the glass is easily broken.

It is also possible that the problems 1) and 2) mentioned above work synergistically. That is, the front glass and the back glass constituting the laminated glass are chemically strengthened float glass, and the float surface is streaked to cut out the glass material. In this case, if the front glass and back glass are attached to the display device so that the float surface faces the back side when viewed from the user (indoor side), the load from the user side is applied to the top surface on the opposite side of the float surface. Since tensile stress is generated on the float surface, there is a problem that the glass is more easily broken than in the cases of 1) and 2) described above.

3) When the float glass is chemically strengthened, the float surface is not easily chemically strengthened, so that a difference in internal stress occurs between the float surface and the top surface, and the float surface warps in a concave shape. Therefore, if the front glass and the back glass made of chemically strengthened float glass are bonded together without aligning the warp directions, there is a problem that the bonding strength and long-term reliability are lowered.

As described above, the windshield disclosed in Patent Document 1 and the laminated glass disclosed in Patent Document 2 both have a structure in which two glass plates are bonded together with an interlayer film. Although it belongs to the same technical field as the laminated glass according to the present invention, it is intended to solve a problem completely different from the above-mentioned problems (problems) found by the inventors of the present application, and is defined in the present invention. It does not disclose or suggest any technical means for solving the above-mentioned problems (problems).

The present invention has been made to solve the problems of the conventional techniques found by the inventors of the present application described above, and the front glass and the back glass are bonded to each other and the back glass is attached to the object to be attached. The purpose of the laminated glass to be attached is to realize high bonding strength and long-term reliability as a whole even if one surface of the front glass and the back glass is weaker than the other surface.

The laminated glass according to claim 1 is
It is a laminated glass in which the front glass and the back glass are bonded together and the back glass is attached toward the object to be attached.
The front glass and the back glass are characterized in that one surface thereof is weaker than the other surface, and the one surface is bonded so as to face the side opposite to the object to be attached. It is supposed to be.

The laminated glass according to claim 2 is the laminated glass according to claim 1.
The front glass and the back glass are formed by folding the plate glass so that the streaks formed on one surface of the plate glass spread, and the one surface is used as the one surface on the opposite side to the mounting object. It is characterized by being pasted together so that it faces.

The laminated glass according to claim 3 is the laminated glass according to claim 1.
The front glass and the back glass are chemically strengthened float glasses, and are characterized in that the float surface in the float method is bonded as one surface so as to face the side opposite to the object to be attached. It is supposed to be.

The laminated glass according to claim 4 is the laminated glass according to claim 1.
The front glass and the back glass are formed by folding the float glass so that the streaks formed on the float surface of the chemically strengthened float glass spread, and the float surface serves as one of the surfaces of the float glass to be attached to the object. Is characterized by being affixed so that it faces the opposite side.

The laminated glass according to claim 5 is the laminated glass according to any one of claims 1 to 4.
The front glass and the back glass are bonded to each other with a heat-resistant adhesive, and the end faces thereof are polished.

According to the laminated glass according to claim 1, the strength of one side of the front glass and the back glass is weaker than the strength of the other side, but each side is on the opposite side to the object to be attached. They are pasted together so that they face each other. Therefore, if the laminated glass is attached to the attachment object so that the surface opposite to one surface of the back glass faces the attachment object, for example, a load from the user side is applied to one surface of the front glass, and the front surface. Even if tensile stress is generated on the other surface of the glass and the back glass, the other surface on the back side has higher strength than the one surface on the front side, so that the laminated glass is not easily broken. Further, since the front glass and the back glass are bonded in the same warp direction, the bonding strength is high and the long-term reliability is also high.

According to the laminated glass according to claim 2, in the front glass and the back glass, the surface on which the streaks are formed at the time of manufacture is one surface in claim 1, and these faces the opposite side to the object to be attached. It is pasted together in such an arrangement. Therefore, if the laminated glass is attached to the attachment object so that the surface opposite to one surface of the back glass faces the attachment object, for example, a load from the user side is applied to one surface of the front glass, and the front surface. Even if tensile stress is generated on the other surface of the glass and the back glass, the other surface on the back side has higher strength than the one surface on the front side, so that the laminated glass is not easily broken.

According to the laminated glass according to claim 3, in the front glass and the back glass, the float surface thereof is one surface according to claim 1, and the laminated glass is attached so as to face the side opposite to the object to be attached. It has been combined. Therefore, if the laminated glass is attached to the attachment object so that the surface opposite to the float surface of the back glass faces the attachment object, for example, a load from the user side is applied to the float surface of the front glass, and the front glass and the surface glass Even if tensile stress is generated on the surface of the back glass opposite to the float surface, the other surface on the back side has higher strength than the float surface, which is one surface on the front side, so the laminated glass is hard to break. ..

According to the laminated glass according to claim 4, in the front glass and the back glass, the float surface on which the streaks are formed at the time of manufacturing is one surface in claim 1, and these are on the opposite side to the object to be attached. It is pasted so that it faces. Therefore, if the laminated glass is attached to the attachment object so that the surface opposite to the float surface of the back glass faces the attachment object, for example, a load from the user side is applied to the float surface of the front glass, and the front glass and the surface glass Even if tensile stress is generated on the surface of the back glass opposite to the float surface, the other surface on the back side has higher strength than the float surface, which is one surface on the front side, so that the laminated glass is not easily broken.

According to the laminated glass according to claim 5, since the front glass and the back glass are bonded with a heatable adhesive that is hardened and exhibits the required rigidity, if the end face is polished after the bonding. Since the heat-resistant adhesive cured together with the front glass and the back glass can be scraped without any trouble, the end face around the laminated glass can be smoothly finished without deforming the laminated structure of the laminated glass.

It is sectional drawing of the laminated glass of 1st Embodiment of this invention. It is a chart which showed the structural drawing, the streak surface, and the fracture strength of each of the laminated glass of 1st Embodiment of this invention and the laminated glass of a comparative example by comparison. It is sectional drawing of the laminated glass of the 2nd Embodiment of this invention.

The laminated glass 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a cross-sectional view of the laminated glass 1 of the first embodiment. The laminated glass 1 is used on the indoor side (that is, on the user side as a driver) in order to give a sense of luxury and transparency in an in-vehicle device such as a car navigation device or a display device such as a speedometer provided on an instrument panel. ) Is a panel-shaped part used as a transparent cover that covers the outermost surface of the exposed part.

As shown in FIG. 1, the laminated glass 1 has a front glass 2 facing the user (driver) facing the indoor side, a back glass 3 to be attached to a display device as an object to be attached, and a front glass 2. It is provided with a heat-resistant adhesive 4 for bonding the back glass 3 to the back glass 3, and a decorative printing layer 5 provided around the back surface of the back glass 3, that is, the front and back surfaces of the back glass 3, which is closer to the display device. ing. The laminated glass 1 is attached to the display device by pointing the side of the back glass 3 toward the display surface of the display device and positioning the entire outer shape so as to match the outer shape of the display surface of the display device. The decorative printing layer 5 is provided for edging the outer shape of the display surface of the display device, displaying the manufacturer's logo, forming a blank portion on which operation switches of the display device are arranged, and the like.

The material of the front glass 2 is a glass plate of soda lime glass having a thickness of 0.5 mm, which is a chemically strengthened float glass manufactured by a float method. The material of the back glass 3 is a glass plate of soda lime glass having a thickness of 0.7 mm, which is a chemically strengthened float glass manufactured by a float method.

On the float surface of each glass plate, which is the material of the front glass 2 and the back glass 3, the above-mentioned carbide wheel is used to make a line along the outer shape of the plate material having a desired size and shape. Next, bend the glass plates on both sides of the streaks so that the streaks are mountain-folded, that is, in the direction in which the width of the streaks widens, and then cut and cut the glass plates along the streaks to the desired size. And obtain a plate material of shape.

The front glass 2 which is a glass plate having a thickness of 0.5 mm cut into a desired shape and size, and the back glass 3 which is a glass plate having a thickness of 0.7 mm cut into the same shape and size as the front glass 2 are formed. Laminated glass 1 is formed by laminating with a film-shaped heat-resistant adhesive 4 cut to the same size as these glass plates. As the heat-sensitive adhesive 4, PVB (polyvinyl butyral), COP (cycloolefin polymer), or the like can be used.

Regarding the orientation of each glass when the front glass 2 and the back glass 3 are bonded together, the float surface (bottom surface) of each glass is set to be on the same side. That is, the surface of the front glass 2 opposite to the float surface (referred to as the top surface) is arranged so as to face the float surface of the back glass 3 with the heatable adhesive 4 sandwiched between them. By doing so, the top surface of the back glass 3 opposite to the float surface (bottom surface) is exposed. Then, if the laminated glass 1 is attached to the display device with the top surface of the back glass 3 facing the display device, the outermost surface of the laminated glass 1 exposed to the indoor side becomes a float surface (bottom surface).

Since the strength of the float surface (bottom surface) of the front glass 2 and the back glass 3 is weaker than that of the top surface, the float surface (bottom surface) is concave and the top surface is convex. However, since the front glass 2 and the back glass 3 are overlapped in the same direction as described above, the directions of warpage are the same, and therefore the bonding work is easy.

After bonding, the treatment is carried out for 30 minutes in an atmosphere of 130 ° C. and 0.8 MPa using a heating and pressurizing furnace. After the heat-sensitive adhesive 4 is cured and firmly bonded, the end face of the laminated glass 1 is polished by a polishing means such as a CNC polishing device. In the first embodiment, the heatable adhesive 4 is used for adhering the front glass 2 and the back glass 3, but when the heatable adhesive 4 is melted at a specific temperature and then cooled and solidified, it has a predetermined rigidity. Since it exhibits hardness, is not viscous at room temperature, and is hardened, it can be mechanically polished in the same state as the front glass 2 and the back glass 3, so that the laminated structure in which the front glass 2 and the back glass 3 are bonded and the laminated structure thereof There is little possibility that harmful or unnecessary changes will occur in the dimensions, etc.

According to the laminated glass 1 of the first embodiment, since the front glass 2 and the back glass 3 to be bonded are warped in the same direction, the warping of the glass has little effect on the bonding strength and has high long-term reliability.

According to the laminated glass 1 of the first embodiment, when pressure is applied from the front surface, that is, the front and back surfaces of the laminated glass 1 as a whole, which is opposite to the surface closer to the display device, the front glass 2 In the back glass 3, the tensile stress that leads to the breakage of the glass is generated on the top surface that has few microcracks and chips and is chemically strengthened, so that the overall bending strength of the laminated glass 1 is high and the laminated glass 1 is easily broken. do not do.

When the laminated glass 1 of the first embodiment is attached to the display device of the instrument panel of the driver's seat of a car as a cover, the outermost surface of the laminated glass 1 exposed to the indoor side is the float surface (bottom surface) of the front glass 2. It becomes. When using a car or the like, it is conceivable that a pressing force (load) is applied to the float surface (bottom surface) of the front glass 2. For example, there is a case where the user touches the operation surface of the display device with a strong force with a finger to operate the display device, or a case where an object in the vehicle collides with the laminated glass 1 with a large force for some reason. Even in such a case, since the tensile stress is generated on the top surface of the front glass 2 and the back glass 3 which has relatively high strength, the overall bending strength of the laminated glass 1 is high and it is difficult to break. It can be said that the possibility of damage and scattering of debris in the car is extremely low.

Next, the breaking strength of the laminated glass 1 of the first embodiment will be described with reference to FIG. 2 while comparing with a comparative example based on specific experimental data.
FIG. 2 is a table showing a comparison of the breaking strengths of the laminated glass 1 (the present invention) of the first embodiment and the laminated glass of the three comparative examples (Comparative Examples 1 to 3). In the present invention and Comparative Examples 1 to 3 shown in FIG. 2, as shown in the column of "cross-sectional view", the front glass 2 and the back glass 3 are each provided with a heat-resistant adhesive 4 (indicated by diagonal lines in the figure). It has a structure bonded with (adhesive 4) (), and as shown in the column of "stranding surface", the bottom surface (that is, the float surface) is streaked, but the "cross-sectional view" is shown. The specific structures of the front glass 2 and the back glass 3 shown in the column are different from each other.

First, in the present invention, as described above, the two bottom surfaces face the side on which the assumed pressing force (indicated by the white arrow) acts. Further, in Comparative Example 1, the bottom surfaces of the front glass 2 and the back glass 3 face the side opposite to the side on which the assumed pressing force acts. Further, in Comparative Example 2, the bottom surface of the front glass 2 faces the side opposite to the side on which the assumed pressing force acts, but the bottom surface of the back glass 3 faces the side on which the assumed pressing force acts. ing. Furthermore, in Comparative Example 3, the bottom surface of the front glass 2 is suitable for the assumed pressing force to act, but the bottom surface of the back glass 3 is oriented to the side opposite to the side on which the assumed pressing force is applied. ing.

The laminated glass 1 of the first embodiment (the present invention) and the laminated glass 1 of the three comparative examples (Comparative Examples 1 to 3) were subjected to a strength test by a four-point bending method. This strength test was performed in accordance with JIS R1601 "Room temperature bending strength test method for fine ceramics". Specifically, the lower surface of the laminated glass 1 is supported by cylindrical support jigs arranged parallel to each other on the base at predetermined intervals, and the lower surface of the laminated glass 1 is supported in parallel with the support jig at an intermediate position between the two support jigs. The upper surface of the laminated glass 1 is pressed downward by two semi-cylindrical load jigs arranged at predetermined intervals. A test in which a load is applied to each laminated glass until it breaks is performed 6 times (n = 6), and the average value of the load applied to the load jig when each laminated glass breaks is the average value of the 6 times of the broken glass. The strength (MPa) was used.

As a result of the above strength test, as shown in the column of "breaking strength [MPa]" in FIG. 2, the present invention was 347 MPa, Comparative Example 1 was 250 MPa, Comparative Example 2 was 311 MPa, and Comparative Example 3 was 276 MPa. It was proved that the strength of the laminated glass 1 was excellent.

In the laminated glass 1 of the first embodiment described above, the heat adhesive 4 was used as the adhesive for adhering the front glass 2 and the back glass 3, but the optical clear adhesive (Optical Clear Adhesive) which is a pressure sensitive adhesive was used. , OCA) may be used for bonding. In that case, after the front glass 2 and the back glass 3 are bonded together, the treatment is carried out in an atmosphere of 50 ° C. and 0.5 MPa for 20 minutes using a heating and pressurizing furnace. Then, the end face of the laminated glass is polished with a CNC polishing device.

In the laminated glass 1 of the embodiment described above, two sheets of the front glass 2 and the back glass 3 are bonded together, but three or more sheets of glass may be bonded together with two or more adhesive layers. .. For example, when three pieces of glass are bonded together, the front glass 2 and the back glass 3 are bonded via an intermediate glass in between. Then, the front glass 2, the back glass 3, and the intermediate glass are all bonded in a state where one surface having a relatively weak strength (or the other surface having a relatively strong strength) is overlapped in the same direction. The glass. Then, if the laminated glass is attached so that the other surface of the back glass 3 having a relatively strong strength faces the object to be attached (for example, an in-vehicle display device), the other surface having a relatively strong strength in each glass is attached. Since the surface is on the side to be attached, even if a large force is applied to the outermost surface of the front glass 2, it is possible to avoid a large tensile stress from being generated on one surface of the three glasses having relatively weak strength. Therefore, the laminated glass can exhibit high breaking strength.

FIG. 3 is a cross-sectional view of the laminated glass 10 of the second embodiment. Its use and structure are substantially the same as those of the first embodiment shown in FIG. 1, but in this laminated glass 10, the decorative printing layer 6 is displayed on the back surface of the front glass 2, that is, the front and back surfaces of the front glass 2. It differs from the first embodiment in that it is provided around the surface on the side closer to the device (that is, the side closer to the back glass 3). The decorative print layer 6 has a thickness of about 10 to 15 μm, but even if it is thin, it has a step. Therefore, if the decorative printing layer 5 is provided on the side (top surface) of the back glass 3 facing the display device as in the first embodiment, the laminated glass 1 may be displayed on the display surface of the display device with an adhesive in some cases. The decorative print layer 5 may interfere with the adhesion when adhering to the glass. In that respect, if the decorative printing layer 6 is provided between the front glass 2 and the back glass 3, it is convenient because the possibility of the above-mentioned problems can be eliminated in advance.

In the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 3, the heat-resistant adhesive is indicated by reference numeral 4, but according to the present invention, the adhesive is not limited to the heat-heat adhesive. Pressure sensitive adhesives can also be used. In this case, the configuration other than the adhesive is the same as that of the first embodiment and the second embodiment. Therefore, FIGS. 1 and 3 can be incorporated as diagrams showing other embodiments when the pressure sensitive adhesive is used, in which case reference numeral 4 indicates the pressure sensitive adhesive in FIGS. 1 and 3. Interpret as a thing.

In the embodiment described above, it was assumed that the float surface (bottom surface) of the float glass was streaked, but the float glass that was chemically strengthened and streaked on the top surface was used as the front glass 2 and the back glass. Even when it is used as the material of No. 3, it is within the scope of the present invention. In this case, for both the front glass 2 and the back glass 3, the strengths of the float surface (bottom surface) without chemical strengthening and the top surface with streaks are compared, and the surface with the lower strength (or the surface with the higher strength) is compared. The sides) may be aligned in the same direction and bonded together so that the side with higher strength faces the object to be attached.

1,10 ... Laminated glass 2 ... Front glass 3 ... Back glass 4 ... Heatable adhesive (or pressure sensitive adhesive)
5 ... Decorative printing layer 6 ... Decorative printing layer

Claims (5)

It is a laminated glass in which the front glass and the back glass are bonded together and the back glass is attached toward the object to be attached.
The front glass and the back glass are characterized in that one surface thereof is weaker than the other surface, and the one surface is bonded so as to face the side opposite to the object to be attached. Laminated glass. The front glass and the back glass are formed by folding the plate glass so that the streaks formed on one surface of the plate glass spread, and the one surface is used as the one surface on the opposite side to the mounting object. The laminated glass according to claim 1, wherein the laminated glass is laminated so as to face each other. The front glass and the back glass are chemically strengthened float glasses, and are characterized in that the float surface in the float method is bonded as one surface so as to face the side opposite to the object to be attached. The laminated glass according to claim 1. The front glass and the back glass are formed by folding the float glass so that the streaks formed on the float surface of the chemically strengthened float glass spread, and the float surface serves as one of the surfaces of the float glass to be attached to the object. The laminated glass according to claim 1, wherein is bonded so as to face the opposite side. The laminated glass according to any one of claims 1 to 4, wherein the front glass and the back glass are bonded to each other with a heat-resistant adhesive, and the end faces thereof are polished.

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