JPH1160294A - Laminated glass for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide laminated glass for vehicles that is constituted with glass plates having a sufficient ion-exchange depth formed by chemical strengthening, additionally in a relatively short treatment time. SOLUTION: In a laminated glass for vehicles that is produced by laminating at least two of single glass plates via an intermediate layer, at least one single glass plate 1 on the outermost surface is a silicate glass, includes lithia (Li2 O) and is chemically strengthened by ion-exchange between Li ion and Na ion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated glass for a vehicle used for a window glass of an automobile or a railway vehicle, and more particularly to a technique in which a chemically strengthened glass plate is applied to a laminated glass for a vehicle.

[0002]

2. Description of the Related Art A glass plate called a safety glass is used as a front windshield glass plate of an automobile. Generally, safety glass includes tempered glass (tempered by air cooling) and laminated glass.

[0003] The air-cooled tempered glass sheet is formed by heating the glass sheet to near the softening point and then rapidly cooling the glass sheet by, for example, blowing air on both sides of the glass sheet to form a compressive stress layer on the surface of the glass sheet. Glass is generally resistant to compressive forces,
Due to the presence of the compressive stress layer, a glass plate having several times the strength of a glass plate (raw plate) not subjected to such treatment is obtained.

On the other hand, as a method of strengthening glass, there is a chemical strengthening method by a so-called ion exchange method, in addition to the above-mentioned air-cooling strengthening.

As a chemically strengthened glass suitable for windshields of automobiles, aircrafts and the like, Japanese Patent Publication No. 47-1312 discloses a lithium or sodium aluminosilicate glass sheet and a method for producing the same. The publication, on the right 29-34 row third term, particularly suitable glass composition, the oxide basis weight inner part, 2~6% Li ₂ O, 5~10
_{% Na 2 O, 15~25% Al} 2 O 3 and 60% to 70%
Consists SiO _2, is at least 95 wt% of _{Li 2 O, Na 2 O,} Al 2 O 3 and total compositions of SiO _2,
There is a description.

Further, WO / 94/08910 (PCT)
/ FR93 / 01035) discloses a glass for windshield of an aircraft or the like, and chemically strengthened glass as a measure against flying objects (bird collision). The chemical tempered glass is weight%
And SiO ₂ : 65.0 to 76.0%, Al ₂ O ₃ : 1.0.
5-50. %, MgO: 4.0 to 8.0%, CaO:
_{0.0~4.5%, Na 2 O: 10.0~18.0} %,
_{K 2 O: 1.0~7.5%, B} 2 O 3: 0.0~4.0%
A composition comprising:

On the other hand, a laminated glass in which two glass plates are laminated with an interlayer film, for example, is widely used as a front windshield glass plate of a passenger car or the like at present.
This is obtained by bonding two glass plates via a PVB (polyvinyl butyral) film, for example.

[0008] In the event that the laminated glass is broken in an accident or the like, the raw plate is a raw plate that has not been strengthened by air cooling, and is broken into large pieces, so that the driver's view is not hindered. A soda lime glass plate by a float method is widely used as a base plate of the laminated glass.

[0009] Japanese Patent Application Laid-Open No. 54-100415 discloses that
"Windshield with chemically strengthened silicate glass inner plate"
, Preferably 1.5 m thick by the full coal method
It is disclosed that a glass plate of m or less is chemically strengthened and used as an inner plate of a windshield. The purpose of this patent is to reduce occupant head damage in low-speed collisions. Specifically, the Severity Index (SI) is 100
The present invention provides a laminated glass of 0 or less. Although the glass composition is not specifically described,
Considering that it is a silicate glass produced by the full coal method, a windshield glass plate, and the like, it is presumed that the soda-lime glass is easy to produce.

[0010]

Incidentally, in a vehicle such as a railroad vehicle or an automobile running at a high speed, there is a case where pebbles and the like on a track or a road surface are hoisted by wind pressure when the vehicle is running. When the rolled-up pebbles and the like fly into the vehicle (hereinafter referred to as stepping stones), the glass surface may be scratched and may even be damaged.

[0011] For this reason, it is required to prevent the glass plate from being damaged due to a stepping stone or the like, which requires replacement of the glass plate, and to prevent the glass plate from being damaged as much as possible.

As a solution to this problem, it is conceivable to first use a wind-cooled tempered glass having a compressive stress formed on its surface to take measures against stepping stones.

However, in the event of breakage, the air-cooled tempered glass plate is broken into small pieces, which obstructs the crew and the driver's view. For this reason, a partially strengthened glass sheet in which the degree of strengthening of the front part of the driver is reduced has been used as a front windshield glass sheet of an automobile.

However, in the front glass of a passenger car,
In Japan, the use of laminated glass is required by law. For this reason, in the front glass of a passenger car, it cannot be used as a single sheet of a tempered glass sheet. In addition, the use of laminated glass is preferred from the viewpoint of safety even in automobiles other than passenger cars.

Further, there is an example in which a laminated glass for a vehicle is formed by using an air-cooled tempered glass plate or a partially tempered glass plate.

When the air-cooled tempered glass sheet is used as a laminated glass and applied to a vehicle, it is considered effective to prevent scratches on the glass surface due to stepping stones or the like due to the formation of compressive stress on the surface. . However, in the unlikely event that the glass is damaged, it will be completely damaged due to the characteristics of the tempered glass. This total damage impairs the visibility of the crew and the driver and gives the passengers and fellow passengers very fear.

Further, even when partially tempered glass is used, the visibility at the time of crushing is improved to some extent, but the visibility of crews and drivers must be obstructed.

That is, when a laminated glass is formed by using a tempered glass plate (including partially tempered glass), if the laminated glass is broken, it will be completely damaged, giving great fear to passengers and passengers, crews and drivers. Adopting it as a stepping stone countermeasure is inconvenient because it obstructs the field of view.

On the other hand, the glass can also be strengthened by the above-mentioned chemical strengthening method based on the ion exchange method.

As a glass sheet for a vehicle, a soda lime composition glass sheet by a float method is often used. In the method of chemically strengthening this soda lime glass plate by an ion exchange method, it is common to exchange and exchange Na ⁺ and K ⁺ from the composition.

However, even if the soda lime glass plate is chemically strengthened, the thickness of the formed surface compression layer can be as thin as at most several tens of μm. For this reason, scratch resistance as a countermeasure against stepping stones may be equal to or worse than that of an unreinforced raw sheet.

Further, since the ion radius of K ⁺ is relatively large and ion exchange takes a relatively long time, it is not industrially desirable. Note that N
The ionic radius of a ⁺ is 0.099 nm and that of K ⁺ is 0.138 nm.

In Japanese Patent Application Laid-Open No. 54-100415, the windshield is made of chemically strengthened silicate glass as an inner plate. Even if chemically strengthened glass is used as the outer plate, a plate glass obtained by the full-coal manufacturing method, specifically, a soda-lime glass plate does not provide an effective countermeasure for stepping stones for the above-described reason.

Further, in the glass having the above composition range described in JP-B-47-1312, a high temperature is required for melting and molding, and it is difficult to produce high-quality glass by a float method.

Further, in WO / 94/08910, a long processing time of at least 72 hours or more, preferably 10 days or more is required for ion exchange, and it is not a cost-effective production method.

Accordingly, the present invention is to provide a laminated glass particularly useful for vehicles, in which a glass sheet having a sufficiently large ion exchange depth formed by chemical strengthening and capable of being processed in a relatively short time is a component. To provide laminated glass for vehicles.

[0027]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, that is, the present invention as defined in claim 1 has at least two single sheets through an intermediate film. In a laminated glass for a vehicle to which a glass plate is adhered, a single glass plate disposed on at least the outermost surface of the glass plates is a silicate glass and contains lithia (Li ₂ O). Further, the single glass plate is a laminated glass for vehicles, wherein the single glass plate is chemically strengthened by ion exchange of Li ions and Na ions.

Further, in the laminated glass for a vehicle according to the first aspect, the single glass plate disposed on the outermost surface is a laminated glass for a vehicle which is a glass plate formed by a float method.

Further, in the laminated glass for vehicles according to claim 1 or 2, the single glass plate disposed on the outermost surface is represented by 58% to 66% by weight of SiO ₂ and Al ₂ O ₃ by weight%. 13 to 19%, Li ₂ O 3 to 4.5%, Na ₂ O 6 to 13%, K ₂ O 0 to 5%, R ₂ O 10 to 18%, (However, R ₂ O = Li ₂ O + Na ₂ O + K ₂ O) MgO 0 to 3.5%, CaO 1 to 7%, SrO 0 to 2%, BaO 0 to 2%, RO 2 to 10%, where RO = MgO + CaO + SrO + BaO) TiO ₂ 0 to 2% _{CeO 2 0~ 2%, Fe 2} O 3 0~ 2%, MnO 0~ 1%, ( provided _{that, TiO 2 + CeO 2 + Fe} 2 O 3 + MnO = 0.
(1 to 3%) is a laminated glass for a vehicle, which is a lithium aluminosilicate glass composition.

Further, in the laminated glass for a vehicle according to claim 3, the single glass plate disposed on the outermost surface is represented by 60% to 66% by weight of SiO _{2 and} 15% by weight of Al ₂ O ₃ 15. １８18%, Li ₂ O 3 to 4.5%, Na ₂ O 7.5 to 12.5%, K ₂ O 0 to 2% (However, Li ₂ O + Na ₂ O + K ₂ O = 11 to 17%) MgO 0.5-3%, CaO 2.5-6%, SrO 0-2%, BaO 0-2%, (however, MgO + CaO + SrO + BaO = 3-9
_{%) TiO 2 0~ 2%,} CeO 2 0~ 2%, Fe 2 O 3 0~ 2%, MnO 0~ 1%, ( provided _{that, TiO 2 + CeO 2 + Fe} 2 O 3 + MnO = 0.
(1 to 3%) is a laminated glass for a vehicle, which is a lithium aluminosilicate glass composition.

Further, in the laminated glass for a vehicle according to any one of claims 2 to 4, the melting temperature (10 ² poise) of the mother glass composition of the single glass plate disposed on the outermost surface.
A laminated glass for vehicles having a temperature of 1550 ° C. or lower, a working temperature (a temperature having a viscosity of 10 ⁴ poise) of 1100 ° C. or lower, and the liquidus temperature of the working temperature or lower.

Further, in the laminated glass for vehicles according to claim 5, the melting temperature (temperature having a viscosity of 10 ² poise) of the mother glass composition of the single glass plate disposed on the outermost surface is 1540 ° C. A laminated glass for vehicles having a working temperature (a temperature having a viscosity of 10 ⁴ poise) of 1055 ° C. or less and the liquidus temperature of the working temperature or less.

Furthermore, in the laminated glass for vehicles according to any one of claims 1 to 6, the ion exchange depth of Na of the chemically strengthened single glass plate is 180 μm or more, and the surface compressive stress is 2000 kg /. This is a laminated glass for a vehicle having a size of not less than cm ² .

The laminated glass for a vehicle according to claim 7, wherein said chemically strengthened single glass plate is made of Na.
Is a laminated glass for vehicles having an ion exchange depth of 400 μm or less and a surface compressive stress of 3000 kg / cm ² or less.

In the first aspect of the present invention, the single glass plate disposed on the outermost surface has a silicate glass composition containing lithia. For this reason, the ion exchange treatment is performed by diffusion exchange between Li ⁺ and Na ⁺ . Since the ionic radius of Li ⁺ is as small as 0.059 nm, that of Li ⁺ and Na ⁺ can be processed in a shorter time than that of ion exchange between Na ⁺ and K ⁺ . In addition, the ion exchange depth can be increased.
Therefore, the present invention has a feature that a sufficiently deep ion exchange depth and a sufficient surface compressive stress can be easily formed.

Further, in the invention according to claim 2,
The single glass plate disposed on the outermost surface is a glass plate formed by a float method. For this reason, it has a feature that it has good flatness, which is a feature of the float method, and can obtain a large raw plate at a low cost at a low cost.

There is no particular limitation on another single glass substrate bonded to the single glass substrate. However, when the laminated glass for a vehicle of the present invention is used as a front glass, an unreinforced glass sheet is used in order to protect the crew and the driver's body (especially the head) in the event of a collision or the like. It is preferably used. As shown in FIG. 1, a single glass plate 1 disposed outside the vehicle is a chemically strengthened glass, and is bonded to another single glass plate 3 by an intermediate film 2 of, for example, PVB.

Further, in the invention according to any one of claims 3 to 6, a specific glassy aluminosilicate glass composition of a single glass plate disposed on the outermost surface is defined, and in addition, the glass composition For products, the melting temperature and working temperature suitable for the float method are also specified.

The reason for limiting the aluminosilicate glass composition containing lithia used in the present invention will be described below.

SiO ₂ is a main component for forming glass and is an essential component. If the proportion is less than 58%, the water resistance after ion exchange deteriorates. on the other hand,
If it exceeds 66%, the viscosity of the glass melt becomes too high, making melting and molding difficult. Therefore, the range of SiO ₂ is preferably 58 to 66%, and more preferably 60 to 66%.

Al ₂ O ₃ increases the ion exchange rate.
It is an essential component for improving the water resistance after ion exchange. If the ratio is less than 13%, the effect is insufficient. On the other hand, if it exceeds 19%, the viscosity of the glass melt becomes too high, and melting and molding become difficult. For this reason, the range of Al ₂ O ₃ is preferably 13 to 19%,
Further, 15 to 19% is preferable.

Li ₂ O is an essential component for performing ion exchange and a component for enhancing solubility.
If the proportion is less than 3%, sufficient surface compression stress after ion exchange cannot be obtained, and the solubility is poor. On the other hand, if it exceeds 4.5%, the water resistance after ion exchange deteriorates and the liquidus temperature rises, making molding difficult. For this reason, Li ₂
The range of O 2 is preferably 3 to 4.5%.

Na ₂ O is a component that enhances solubility. If the ratio is less than 6%, the effect is insufficient. On the other hand, if it exceeds 13%, the water resistance after ion exchange deteriorates. Therefore, the range of Na ₂ O is preferably from 6 to 13%, more preferably from 7.5 to 12.5%.

K ₂ O is a component that enhances solubility, but is not an essential component because the surface compressive stress after ion exchange decreases. For this reason, the range of K ₂ O is preferably 5% or less, more preferably 2% or less.

Further, if the total R ₂ O of Li ₂ O + Na ₂ O + K ₂ O is less than 9%, the viscosity of the glass melt becomes too high, and melting and molding become difficult. On the other hand, if it exceeds 18%, the water resistance after ion exchange deteriorates. Therefore, Li ₂ O
The range of the total R ₂ O of + Na ₂ O + K ₂ O is preferably 9 to 18%, more preferably 10 to 17%.

MgO is a component that enhances solubility.
If it exceeds 3.5%, the liquidus temperature rises and molding becomes difficult. For this reason, MgO is preferably 3.5% or less, more preferably 0.5 to 3%.

CaO is a component that enhances solubility and is an essential component for adjusting the ion exchange rate.
If the ratio is less than 1%, the effect is not sufficient. on the other hand,
If it exceeds 7%, the liquidus temperature rises and molding becomes difficult.
For this reason, the range of CaO is preferably 1 to 7%, and more preferably 2.5 to 6%.

SrO and BaO are components that enhance the solubility and are effective components for lowering the liquidus temperature.
However, as the density of the glass increases, the cost of raw materials increases. Therefore, SrO and BaO are each preferably 2% or less, and more preferably 1% or less.

Further, MgO + CaO + SrO + BaO
If the total RO is less than 2%, the viscosity of the glass melt becomes too high, making melting and molding difficult. If it exceeds 10%, the liquidus temperature rises and molding becomes difficult. For this reason, MgO
The range of the total RO of + CaO + SrO + BaO is 2
-10% is preferable, and 3-9% is more preferable.

Fe ₂ O ₃ is composed of Fe ²⁺ and Fe ^{3+ in the} glass melt.
Are in an equilibrium state, and these ions greatly affect the transmittance of light in the melt, particularly the transmittance in the infrared region. All iron to Fe
Above 2% in terms of ₂ O ₃ , the absorption in the infrared region becomes too large, making it impossible to control the temperature distribution of the glass during melting or molding, leading to deterioration in quality. Therefore, the total iron is F
e ₂ O ₃ is preferably 2% or less.

TiO ₂ , CeO ₂ and MnO are composed of Fe ²⁺ and Fe
It is an effective component for changing the equilibrium state of ³⁺ and for changing the light transmittance by interacting. However, an excessive content lowers the quality of the glass base and leads to an increase in raw material costs. Therefore, the range of TiO ₂ is preferably 3% or less, more preferably 2% or less. Further, the range of CeO ₂ and MnO is preferably 1% or less.

Further, in addition to the above components, a coloring agent such as NiO, Cr ₂ O ₃ , CoO and a fining agent such as SO ₃ , As ₂ O ₃ , Sb ₂ O ₃ are provided as long as the characteristics of the present invention are not impaired. Agents can be included.

Of these, SO ₃ is derived from sulfate used as a fining agent. When sulfate is used as a fining agent, the fining effect is not sufficient if the residual amount in the glass is less than 0.05%. . On the other hand, even if the residual amount exceeds 0.5%, the refining effect is the same, and the SOx contained in the exhaust gas at the time of melting the glass increases, which is not environmentally preferable. Therefore, SO ₃ remaining in the glass is 0.05%
~ 0.5% is preferred.

Further, As, which is generally used as a fining agent,
_The content of ₂ O ₃ and Sb ₂ O ₃ is preferably 1% or less due to its toxicity, and is preferably not more than the amount mixed with impurities, that is, 0.1% or less.

Further, highly volatile B ₂ O ₃ , ZnO, P ₂
O ₅ , PbO, etc. erode the bricks of the glass melting furnace and also deteriorate the quality such as volatile components aggregating on the ceiling of the furnace and dropping on the glass together with the bricks. The content is preferably set to 0.1% or less.

[0056] viscosity of the glass is to dissolve the high-quality glass, the melting temperature that is preferably 1550 ° C. or less temperature having the viscosity of 10 ² poise, further 1540 ° C. or less. Also, to form a sheet with high flatness,
In particular, when forming by the float method, the working temperature, ie, 1
It is preferable that the temperature having a viscosity of 0 ⁴ poise be 1100 ° C. or lower and the liquidus temperature be lower than the working temperature. Further, it is desirable that the working temperature be 1055 ° C. or lower and the liquidus temperature be lower than the working temperature.

Further, in the laminated glass for vehicles according to claim 7, the ion exchange depth of Na of the chemically strengthened single glass plate is 180 μm or more and the surface compressive stress is 2 μm.
000 kg / cm ² or more. Having the ion exchange depth and the surface compressive stress exerts a sufficient effect as a stepping stone countermeasure.

The ion exchange depth of Na is as follows.
It may be 180 μm or more. The technical upper limit is the range obtained by performing chemical strengthening. The ion exchange depth is basically determined by a function of the temperature of the molten salt and the immersion time. The ion exchange depth can be increased by increasing the temperature as much as possible and / or increasing the ion exchange time at a temperature within a range where the glass does not deform.

However, as will be described in detail below (embodiments of the invention), for example, in the case of performing ion exchange with a molten salt at 380 ° C., if an ion exchange depth exceeding 400 μm is to be obtained, it takes more than two days. , And even if it exceeds 300 μm, it takes more than one day. Therefore, considering the productivity, the upper limit of the ion exchange depth is 400 μm
Or less, and more preferably 250 μm or less.

Further, the surface compressive stress was 2000
It suffices if it is at least kg / cm ² . The technical upper limit is the range obtained by performing chemical strengthening. The obtained surface compressive stress is basically determined by the amount of Li ions in the glass composition and the rate at which Li ions near the surface are exchanged for Na ions.

On the other hand, the introduced compressive stress is reduced when the temperature of the molten salt is high or the immersion time in the molten salt is long. That is, the upper limit of the surface compressive stress that can be introduced is about 3000 kg / cm ² .

Therefore, in the laminated glass for a vehicle according to the present invention, the chemically strengthened single glass plate of Na
Has an ion exchange depth of 400 μm or less and a surface compressive stress of 3000 kg / cm ² or less.

The laminated glass for a vehicle of the present invention can be manufactured by the following method. That is, a silicate glass plate containing lithia (Li ₂ O) is prepared, immersed in a molten salt of sodium nitrate, and chemically strengthened by ion exchange between Li ions and Na ions. This glass substrate is arranged on the outermost surface of the laminated glass for a vehicle, and another optional single glass substrate and PV
Adhering via a B film interlayer.

Further, as long as the chemically strengthened glass plate is disposed on the outermost surface of the laminated glass for a vehicle, three or more single glass plates are bonded via an intermediate film as necessary, and It can also be used as a laminated glass.

Further, it is preferable that the single glass substrate to be chemically strengthened is manufactured by a float method as described in claim 2.

Further, the single glass substrate to be chemically strengthened is preferably an aluminosilicate glass composition containing lithia, as described in claims 3 and 4.
In addition, claim 5 and claim 6 in the glass composition.
It is preferable to have the melting temperature and the working temperature described in (1) when manufacturing by the float method.

Further, as a modified example of the method for producing the present invention, the following forms can be considered. That is, in the method for manufacturing a laminated glass for a vehicle in which at least two single glass plates are bonded via an intermediate film, a single glass plate disposed on at least the outermost surface of the glass plates is:
It is a silicate glass and contains lithia (Li ₂ O). Further, after bending the single glass plate, it is chemically strengthened by ion exchange of Li ions and Na ions, and is bent. A laminated glass for a vehicle, wherein the laminated glass is bonded to a single glass substrate through an intermediate film.

In this manufacturing method, a single glass plate disposed on the outermost surface is bent and then chemically strengthened by ion exchange in the method for manufacturing a laminated glass for a vehicle.
It is bonded to another bent single glass substrate via an intermediate film. However, in wind-cooling bending strengthening, bending and strengthening steps are performed simultaneously. For this reason, there is naturally a limit to the shape that can be formed.

On the other hand, in the manufacturing method described above, since the tempering and bending steps are performed separately, it is possible to manufacture a laminated glass for a chemically strengthened vehicle having a curved shape that cannot be formed by air cooling. Have.

[0070]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
[Chemically Tempered Glass Plate] First, in the present invention, a chemically strengthened glass plate disposed on the outermost surface will be described. Glasses of the lithialuminosilicate composition shown in Table 1 were produced by a float method. The plate thickness was about 5 mm. In addition,
It is expressed in weight%.

[0071]

TABLE 1 _{------------- SiO 2 63.0 Al 2 O 3} 16.3 Li 2 O 3.7 Na 2 O 10.6 K 2 O 0.4 MgO 1. 9 CaO 3.8 TiO ₂ 0.02 Fe ₂ O ₃ 0.08 SO ₃ 0.2 −−−−−−−−−−−−−−−

The glass of the above composition has the melting point, working point and liquidus temperature shown in Table 2, and is a composition that can be produced by the float method.

[0073]

Table 2 Melting point (° C) 1522 Working point TW (° C) 1039 Strain point (° C) 469 Liquidus temperature TL (° C) 1002 Transition point Tg (° C) 512 −−−−−−−−−−−−−−−−−−−−

The ion exchange treatment was performed as follows. First, sodium nitrate was placed in a stainless steel container, heated once to about 500 ° C., and kept at that temperature for about 30 minutes to remove impurities. Next, the lithium aluminosilicate glass plate was heated to about 400 ° C., and then immersed in the molten salt maintained at a predetermined temperature to perform an ion exchange treatment. The ion exchange treatment at this time was performed by diffusion exchange between Li ⁺ and Na ⁺ . After holding for a predetermined treatment time, the glass plate was taken out of the molten salt and gradually cooled to room temperature. Thereafter, it was thoroughly washed with city water.

The sample prepared in this manner was used in XM
A was used to measure the Na ion exchange depth. The measurement conditions are as follows. Measurement conditions:-Equipment used: JXA8600-Measurement method: line analysis
Acceleration voltage: 15 kV,

The surface compression stress was measured by a polarizing microscope. First, for sample preparation, a sample glass was cut in a cross-sectional direction with a fine cutter, polished to a thickness of about 300 μm, and provided for measurement. Next, the amount of strain was measured with a Senarmon convencator and converted into surface compressive stress.

(Preliminary Experiment) The above-mentioned lithialuminosilicate glass plate was immersed in a molten salt of sodium nitrate to perform ion exchange. First, samples were prepared at a treatment temperature of 340 ° C. and two dipping times of 8 hours and 16 hours. Table 3 shows the results.

[0078]

Table 3------------------------------------------------------immersion time Na exchange depth Surface compressive stress Stress layer thickness (Hr) (μm ) (Kg / cm ² ) (μm) −−−−−−−−−−−−−−−−−−−−−−−−−−−− 8 160 1880 45 16 210 210 2270 65 −−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Using this sample, a stone impact test described later was performed (see Table 6). As a result, 34
The number of defective samples in the chemically strengthened sample subjected to the ion exchange treatment at 0 ° C. × 8 hours was not much different from that of the unstrengthened and air-cooled samples with soda lime glass composition, and the effect was not observed.

However, in the chemically strengthened sample subjected to the ion exchange treatment at 340 ° C. × 16 Hr, the number of defectives was smaller than that of the unreinforced and air-cooled soda lime glass composition, and the effect was recognized.

That is, the ion exchange depth of Na is 180 μm.
m or more and a surface compressive stress of 2000 kg / cm ² or more, it was found that the glass had sufficient performance as a chemically strengthened single glass plate constituting a laminated glass for preventing stepping stones.

Further, samples were prepared under various ion exchange conditions using the above-mentioned lyaluminosilicate glass plate. The treatment temperature was 340 to 460 ° C, and the immersion time was changed to 8 to 96 hours.

(Study on Ion Exchange Conditions) First, the temperature of the molten salt was kept constant at 380 ° C., and the immersion time was changed from 8 to 96 hours. Table 4 shows the results.

[0084]

Table 4---------------------------------------------immersion time Na exchange depth Surface compressive stress Stress layer thickness (Hr) (μm ) (Kg / cm ² ) (μm)---------------------------8 200 2600 80 16 210 210 2616 100 24 300 2926 105 40 310 2714 115 64 380 2935 130 96 420 2874 110 110 ------------------------------------------------------

From Table 4, when the molten salt temperature is fixed,
It can be seen that the longer the immersion time, the deeper the ion exchange depth of Na. However, if the immersion time of the surface compressive stress is too long, ion exchange proceeds while stress relaxation also progresses, so that no tendency for a change in surface compressive stress was found. As for the compressive stress layer, there was a tendency that the thickness increased as the immersion time increased.

Next, assuming that the immersion time is constant for 16 hours,
The molten salt temperature was changed from 340 to 460 ° C. Table 5 shows the results.

[0087]

[Table 5] ------------------------------------------------ Molten salt temperature Na exchange depth Surface compressive stress Stress layer thickness (° C) (Μm) (kg / cm ² ) (μm) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 340 210 2270 65 380 300 2860 110 420 330 2570 100 460 450 1480 80 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Table 5 shows that when the immersion time is fixed, the higher the molten salt temperature, the deeper the ion exchange depth of Na. However, it has been found that when the molten salt temperature is too high, ion exchange progresses while stress relaxation also progresses, so that the surface compressive stress decreases to a peak at 380 ° C. A similar tendency was observed for the thickness of the compressive stress layer.

As described above, by subjecting a lithialuminosilicate glass plate to an ion exchange treatment by selecting an appropriate immersion time and a molten salt temperature, the ion exchange depth of Na is reduced to 1%.
It has become possible to produce chemically strengthened glass having a surface compression stress of 80 μm or more and 2000 kg / cm ² or more.

As one of suitable ion exchange conditions, 380 ° C. × 8 hours can be shown.

(Stone Impact Test) A chemically strengthened sample of a lithia aluminosilicate glass plate having the actual dimensions of a railway vehicle window described above was prepared. For comparison, an unstrengthened sample of a soda lime silicate glass plate and an air-cooled tempered (double-strength glass: semi-tempered) sample were also prepared.

These sample glasses were placed outside the laminated glass for vehicles, and the unstrengthened soda lime silicate glass plate (plate thickness: 2 mm) by the float method was placed inside, and the glass was sandwiched between the PVB interlayers. A laminated glass sample was prepared (see FIG. 1).

About 30 g of pebbles weighing about 2 g were blasted with an air gun at 30 places on the surface of each sample glass.
A stone impact test was performed by colliding these glass substrates at m / h and a collision incident angle of 0 °. This is a test considering application to the front of a vehicle. In addition, the evaluation is "4
The part having a scratch of not less than mm and the part that was "broken" were judged to need replacement, and were counted as the number of defects.

[0094]

Table 6 When the incident angle of collision = 0 degrees -------------------------------------------------- Outside glass Sorter lime silicate Lithia aluminosilicate chemical strengthening --------------------------------------- Strengthening conditions Not strengthened Air cooling strengthened 340 ℃ × 8Hr 340 ℃ × 16Hr 380 ℃ × 8Hr −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Flaw size 2mm or less 0/30 2/30 1/30 4 / 30 0/30 2-4mm 7/30 9/30 5/30 11/30 18/30 4mm or more 12/30 10/30 13/30 7/30 3/30 Crack 14/30 9/30 11/30 8 / 30 9/30 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Total defects 26/30 19/30 24/30 15/30 12/30 ------------------------------------------------------------------------------------

From Table 6, when the collision incidence angle is 0 degree, the following can be said when evaluated based on the above-mentioned criteria.

340 ° C. × 16 hours, and 380 ° C. × 8
The samples prepared under the Hr ion exchange conditions resulted in a smaller total number of defectives than not only non-strengthened soda lime silicate glass but also air-cooled tempered.

Further, a stone impact test was conducted on an unstrengthened soda lime silicate glass, a tempered by air cooling, and a chemically strengthened lithialuminosilicate at 380 ° C. × 8 hours at an incident angle of incidence of 60 °. This is a test considering application to side glass. The evaluation is the same as in the case where the incident angle of the collision = 0 °.

[0098]

[Table 7] When the incident angle of collision = 60 degrees --------------------------------- Outside glass Sorter Lime silicate Lycia aluminosilicate ---------------------- −−−−−−−−−−−−−−−− Flaw size 2 mm or less 4/30 11/30 8/30 2 to 4 mm 18/30 15/30 21/30 4 mm or more 8/30 3/30 1/30 Cracked 0/30 1/30 0/30 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Total defects 8/30 4 / 30 1/30 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

According to Table 7, when the incident angle of the collision = 60 degrees,
When evaluated based on the above criteria, it can be seen that the lithia aluminosilicate chemically strengthened product at 380 ° C. × 8 Hr shows better results than the air-cooled soda lime silicate glass product.

(Crushing Pattern) FIG. 2 shows an example of a crushed state of a chemically strengthened laminated glass of lycia aluminosilicate and an unreinforced laminated glass of soda lime silicate in a stone impact test. (A) is a chemically strengthened laminated glass, and (b) is an unreinforced laminated glass. The sample was 100 mm square.

It was found that the chemically strengthened laminated glass was crushed into large pieces when crushed. further,
It was found that there were many cases of crushing with larger fragments as compared with unreinforced glass. In the case of unstrengthened laminated glass, large breaks were often observed at the starting point of the breakage where the pebbles collided. In contrast, in the case of chemically strengthened laminated glass, such chipping was rarely observed.

[Application Example] A lithialuminosilicate glass plate produced by a float method was cut into a predetermined windshield shape of a railway vehicle or an automobile, and then chemically strengthened. The glass plate and the soda lime silicate glass plate of the float method were bonded together via a PVB film to produce a laminated glass for a chemically strengthened vehicle. In this case, the laminated glass for a chemically strengthened vehicle may be a flat plate or may be subjected to a bending process depending on the design of a railway vehicle or an automobile.

The above application example is an example of a windshield for a railway vehicle or an automobile. However, the present invention is not limited to this, and it goes without saying that the present invention can also be applied to a side window glass plate.

Further, in the above-described example, two single glass plates were bonded with an interlayer film to form a laminated glass for vehicles. However, it is needless to say that there are no difficulties in forming three or more laminated glasses for vehicles according to the place of application and its necessity, and it is needless to say that this is within the technical scope of the present invention.

(Reference Comparative Example) An example in which a glass plate of a soda lime silicate composition, which is widely used as a window glass plate for a vehicle and is float-processed, is subjected to ion exchange will be described.

First, a glass plate having a soda lime silicate composition and having a thickness of 5 mm prepared by a float method was prepared. This glass plate was immersed in a molten salt of potassium nitrate (temperature: 460 ° C.) to perform an ion exchange treatment. The immersion time was 4 to 64 hours. The ion exchange treatment at this time was performed by diffusion exchange between Na ⁺ and K ⁺ .

[0107]

Table 8-------------------------------------------------immersion time K exchange depth Surface compressive stress Stress layer thickness (Hr) ( μm) (kg / cm ² ) (μm)---------------------------------------------------------------------------------------------------- 40 3450 30 ----------------------------------------------------------------------------------

Table 8 shows that when a soda lime composition glass plate is subjected to ion exchange by diffusion between Na ⁺ and K ⁺ , a surface compression stress of 2700 kg / cm ² or more can be obtained. However, the formed K ion exchange depth was only 40 μm at most.

[0109]

As described above, the present invention has the following effects. The invention according to claim 1, wherein the single glass plate disposed on the outermost surface has a silicate glass composition containing lithia, and further includes Li ⁺
Chemical strengthening by ion exchange with Na ⁺ .
Therefore, the ion exchange treatment can be performed in a short time. In addition, the ion exchange depth can be increased. Therefore, the present invention has a feature that a sufficiently thick compressive stress layer effective as a measure against stepping stones can be easily formed.

As described above, since the chemically strengthened single glass plate is used as a laminated glass for vehicles, even if it is broken, since the internal stress is small, it does not lead to total damage like wind-cooled tempered glass. And fear of giving crew members little fear. For crews and drivers,
View is secured.

In the invention described in claim 2, in addition to the invention described in claim 1, the single glass plate disposed on the outermost surface is a glass plate formed by a float method. For this reason, there is no need to polish the glass plate or the like, and the glass plate is characterized by being able to obtain a large-sized raw plate at low cost.

Further, in the inventions according to the third to sixth aspects, a specific lithialuminosilicate glass composition is defined, and in addition, a melting temperature and a working temperature suitable for the float method are set in the glass composition. Also stipulates. Therefore, the glass composition of the present invention has characteristics that can be favorably applied to the float method.

Further, in the invention according to claim 7,
The ion exchange depth of Na of the chemically strengthened single glass plate disposed on the outermost surface of the laminated glass is 180 μm or more, and the surface compressive stress is 2000 kg / cm ² or more.

Having such an ion exchange depth and surface compressive stress is effective in preventing stepping stones.

Furthermore, in the invention according to claim 8, the ion exchange depth of Na of the chemically strengthened single glass plate is 400 μm or less and the surface compressive stress is 30 μm.
It is supposed to be 00 kg / cm ² or less.

With such ion exchange depth and surface compressive stress, it is effective as a countermeasure against stepping stones, and it is possible to perform chemical strengthening excellent in productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of the present invention.

FIG. 2 is a view showing a state of crushing with a laminated glass for a vehicle.

[Explanation of symbols]

 Reference Signs List 1 single glass plate chemically strengthened 2 interlayer film (PVB) 3 single glass plate

Claims (8)

[Claims] 1. A laminated glass for vehicles to which at least two single glass plates are bonded via an interlayer film, wherein the single glass plate disposed on at least the outermost surface of the glass plates is a silicate. Glass and Lithia (L
A laminated glass for vehicles, wherein i ₂ O) is contained, and the single glass plate is chemically strengthened by ion exchange of Li ions and Na ions. 2. The laminated glass for vehicles according to claim 1, wherein the single glass plate disposed on the outermost surface is a glass plate formed by a float method. 3. The laminated glass for vehicles according to claim 1, wherein the single glass plate disposed on the outermost surface is represented by weight%: SiO ₂ 58 to 66%, Al ₂ O ₃ 13 to 19%, Li ₂ O 3 to 4.5%, Na ₂ O 6 to 13%, K ₂ O 0 to 5%, R ₂ O 10 to 18%, (However, R ₂ O = Li ₂ O + Na ₂ O + K ₂ O) MgO 0 to 3.5%, CaO 1 to 7%, SrO 0 to 2%, BaO 0 to 2%, RO 2 to 10%, where RO = MgO + CaO + SrO + BaO) TiO ₂ 0 to 2% _{CeO 2 0~ 2%, Fe 2} O 3 0~ 2%, MnO 0~ 1%, ( provided _{that, TiO 2 + CeO 2 + Fe} 2 O 3 + MnO = 0.
(1-3%), a laminated glass for vehicles, which is a lithialuminosilicate glass composition. 4. The laminated glass for vehicles according to claim 3, wherein the single glass plate disposed on the outermost surface is represented by 60% to 66% of SiO _{2 and} 15% to 15% of Al ₂ O ₃ by weight%. 18%, Li ₂ O 3 to 4.5%, Na ₂ O 7.5 to 12.5%, K ₂ O 0 to 2% (however, Li ₂ O + Na ₂ O + K ₂ O = 11 to 17%) MgO 0.5-3%, CaO 2.5-6%, SrO 0-2%, BaO 0-2%, (however, MgO + CaO + SrO + BaO = 3-9
_{%) TiO 2 0~ 2%,} CeO 2 0~ 2%, Fe 2 O 3 0~ 2%, MnO 0~ 1%, ( provided _{that, TiO 2 + CeO 2 + Fe} 2 O 3 + MnO = 0.
(1-3%), a laminated glass for vehicles, which is a lithialuminosilicate glass composition. 5. The laminated glass for a vehicle according to claim 2, wherein a melting temperature of a mother glass composition of a single glass plate disposed on the outermost surface (a temperature having a viscosity of 10 ² poise). ) Is 15
A laminated glass for vehicles having a working temperature (a temperature having a viscosity of 10 ⁴ poise) of 1100 ° C. or less and a liquidus temperature of the working temperature or less at 50 ° C. or less. 6. The laminated glass for a vehicle according to claim 5, wherein the melting temperature (temperature having a viscosity of 10 ² poise) of the mother glass composition of the single glass plate disposed on the outermost surface is 15.
A laminated glass for vehicles having a working temperature (a temperature having a viscosity of 10 ⁴ poise) of 1055 ° C. or less and a liquidus temperature of the working temperature or less at 40 ° C. or less. 7. The laminated glass for vehicles according to claim 1, wherein the chemically strengthened single glass plate has an ion exchange depth of Na of 180 μm or more and a surface compressive stress of 2000 k.
g / cm ² or more laminated glass for vehicles. 8. The laminated glass for a vehicle according to claim 7, wherein the chemically strengthened single glass sheet has an ion exchange depth of Na of 400 μm or less and a surface compressive stress of 3000 k.
g / cm ² or less for laminated glass for vehicles.