WO2001034531A1

WO2001034531A1 - Flat glass to be tempered

Info

Publication number: WO2001034531A1
Application number: PCT/JP2000/007881
Authority: WO
Inventors: Hiromitsu Seto; Shigekazu Yoshii
Original assignee: Nippon Sheet Glass Co., Ltd.
Priority date: 1999-11-11
Filing date: 2000-11-09
Publication date: 2001-05-17
Also published as: JP4951838B2; WO2001034531B1

Abstract

A flat glass to be tempered, characterized in that it forms, when it is subjected to thermal tempering treatment, a tempered glass having a thermal tempering coefficient, which is represented by a quotient obtained by dividing a surface compression stress (MPa) by a sheet thickness, of 35 to 75; and a composition of glass for the flat glass. The flat glass has preferably a thermal stress coefficient represented by a product of an average coefficient of linear expansion and a Young's modulus of 0.70 to 1.20 Mpa/?C. The flat glass can be used for producing a thin tempered flat glass which has a real thickness of 6 mm or less, preferably 3.1 mm or less, and exhibits a satisfactory surface compression stress without increasing the capacity of a tempering process to be used.

Description

Item ΐ Tempered glass sheet Technical field

The present invention relates to a tempered glass sheet, and in particular, relates to a thermal strengthening coefficient (= [surface compressive stress] Z [thickness) expressed by a quotient obtained by dividing the surface compressive stress value (MPa) of glass by the thickness (mm) of the sheet. ]) Relates to a tempered glass sheet having a specific range. Background art

Except for special cases, glass fracture starts at the surface, and occurs when the tensile stress that appears on the glass surface due to external forces exceeds the tensile strength of the glass. The durability of a glass to tensile stress is greatly affected by microscopic flaws called Griffith flaws on the glass surface. Therefore, in order to increase the strength of glass, it is effective to provide a compressive stress layer on the glass surface to alleviate the tensile stress due to external force and prevent the growth of cracks. The compressive stress layer on the glass surface is formed by chemical strengthening and physical strengthening.

According to this physical strengthening method, high-temperature glass is quenched, and at room temperature, residual stress is generated in the thickness direction of the glass, and a compressive stress layer is formed on the surface. The most widely used physical strengthening method is the air-cooling strengthening method using air cooling. According to the air-cooling tempering method, the glass is heated to a temperature near the softening point, and then the surface of the glass is quenched by a pressurized air flow, so that a compressive stress layer is formed on the glass surface, and the inside of the glass is pulled. A stress layer is formed.

It is known that the surface residual stress of a glass sheet generated by the air-cooling strengthening method depends on the temperature difference between the surface and the inside during cooling. Assuming that the heat dissipation Q from the glass is constant, the maximum temperature difference between the glass surface and the inside (△ 0) max is as follows: (Α Θ) max = t Q / 8 k

[t: Glass thickness (m), Q: heat radiation amount ^{(J / m 2 'h)} , k: thermal conductivity (J / m'h' ° C) ] is approximated with. Assuming that the strain relaxation time is sufficiently short and that no change in the temperature gradient occurs during the cooling stage, the compressive stress F on the glass surface at room temperature is as shown in Equation 1.

α Ξ 2

F = (厶) max

(1-cr) 3

[G: coefficient of linear expansion, E: Young's modulus, and: Poisson's ratio]

The parameters of thermal conductivity, coefficient of linear expansion, Young's modulus, and Poisson's ratio are values determined by the glass composition. Here, since the compressive stress value of the glass plate is approximately proportional to the thickness of the glass, dividing this by the plate thickness gives the magnitude of the compressive stress determined by the physical properties of the glass itself. That is, the contribution of the glass composition to the compressive stress value is determined. Here, this value is called the thermal strengthening coefficient. Larger heat strengthening coefficients indicate that the glass has a composition that is more easily reinforced.

Conventionally, the thickness of float glass used for automotive windows was mainly 3.5 to 4.8. In recent years, there has been a strong demand for thinner window glasses to improve fuel efficiency by reducing the weight of automobiles. If the area is the same, the thinner the thickness, the smaller the heat capacity of the glass sheet, and the more difficult it becomes to strengthen. Therefore, several tempered glasses have been proposed to compensate for this.

The production method of tempered glass described in Japanese Patent Publication No. 6-535992 is essentially expressed in terms of% by weight.

S i 0 ₂ : 6 3 -7 5,

A 120 _3: 1. 5~7,

T i 0 ₂ : 0 to 6,

_{AI2O3 + T i 0 2: 3~7} , C a 0: 5 to 15;

MgO: 0-: L 0,

CaO + MgO: 6-20,

N a ₂ 〇: 8 to: 18,

K ₂ 0: 0~5,

Na ₂₀ + K ₂₀ : 10-20

Wherein the liquidus temperature of the glass is 110 ° C. or lower.

The easily strengthened glass composition disclosed in JP-B-4-160059 is expressed in terms of% by weight,

S i 0 ₂ : 68.0-71.0,

_{A 120 3:. 1. 6~3 0} ,

C a 0: 8.5-11.0,

MgO: 2.0-4.0,

N a ₂₀ : 12.5 to 16.0,

K ₂ 〇: 0.9 to 3.0,

The sum of these components is 97% or more, and

S i O 2 + A 12 O 3: 70.0-73.0,

C aO + MgO: 12.0 to 15.0,

Na ₂₀ + K ₂₀ : 13.5-17.0

Consists of compositional component ranges, moreover 1 0 ⁹ viscous temperature viscosity temperature becomes Boyes becomes 6 5 0~ 6 8 5 ° C and 1 0 ¹² Boys is 55 5~585 ° C, and the temperature difference between the two Is in the range of 96 to 103 ° C. The Kokoku 6 - In 535 92 JP process for the preparation of tempered glass according to, A 120 ₃ added amount is large, and requires at least 3% if you look at the _{_{A l 2 0 3 + T i}} 0 2 quantity. To obtain a clear glass, it is necessary to add a large amount of A 1 ₂ 0 ₃ to avoid the addition of T i 0 _2, there is a disadvantage that a very poorly soluble composition. Also implemented In the examples, there is an example of strengthening the glass with a thickness of 3 mm. However, although the strengthening conditions were improved, the surface compressive stress value was insufficient.

Also the Kokoku 4 one 6 00 5 9 No. flat glass composition disclosed in Japanese is something to obtain an easy-tempered glass by adjusting the viscosity temperature, 1 0 ⁹ temperature difference Boyes and 1 0 ¹² Boi's However, the allowable range was only as small as 7 ° C, and the allowable composition range was so narrow that production was difficult. Disclosure of the invention

The present invention has been made in view of the above-mentioned problems of the related art, and is a glass plate having an actual thickness of 6 mm or less, more preferably 3.1 mm or less, which substantially enhances the capacity of a strengthening process. It is an object of the present invention to provide a thin sheet tempered glass having a sufficient surface compressive stress value, a glass composition constituting the same, and a sheet glass composed of the composition, without requiring the following.

The tempered glass sheet of the present invention has a heat strengthening coefficient expressed by a quotient obtained by dividing a surface compression stress value (MPa) by a sheet thickness (mm) when the glass sheet is subjected to tempering treatment, of 35 to 75. Becomes Preferred embodiments of the invention

The glass sheet preferably has an actual thickness of 6 mm or less, more preferably 3.1 mm or less.

The tempered glass sheet is preferably strengthened by an air-cooling tempering method. More preferably, the thermal strengthening coefficient is 45 to 65.

. 5 0 ° C; ~ 3 5 0 average coefficient of linear expansion in ° C (. ¹⁾ and the thermal stress factor you express the product of Young's modulus (GPa) is preferably 0. 70~: L 2 0MP a / ° C, more preferably 0.72 to 0.8 OMP a /. C.

The reinforcing plate glass is preferably 5 0 ° C~ 3 5 0 average linear expansion coefficient ° C is ^{92 X 1 0- 7 ~ 1 0} 5 X 1 0- 7 ° C- and Young's modulus 7 5-9 2 GPa. More preferably the reinforcing plate glass, the average linear expansion coefficient ^{9 5 X 10- 7 ~ 1 0} 0 X 10- 7 ° C- ', and Young's modulus of 77 to 85 GP a.

The preferred base glass composition of the tempered sheet glass is expressed in mole fraction,

45〜70% 3 丄 0 ₂ヽ

0-5% of 8 ₂ 0 ₃ヽ

0.5 ~: L 5% of 8 1 ₂ 0 ₃ ,

2.5-20% of 1 g 0,

7. 5-30% 〇 & 0,

0 to 10% S r 0,

0 to: 8 a 0 of L 0% (However, the sum of MgO, C a 0, S r 0, and B a OS is more than 10% and less than 50%)

0 to 10% L i ₂₀ ,

9-25% Na ₂ 0,

0-1 5% 1 ₂ 0, (where, L i ₂ 0, N a ₂ 0, K ₂ 〇 amount of total 10% or more 4

0% or less,)

0 ~: L 5% 丫₂ 〇 ₃ ,

0-1 5% 1 a ₂ 0 _3,

And 0-15% Zr 0 ₂

The base glass composition may contain the following coloring components, expressed as a mole fraction, whereby the transmittance of ultraviolet light, infrared light and visible light is adjusted.

Total iron oxide in terms of 0.3 to 4% of _{_{F e 2 0 3 (T- F}} e 2 0 3)

0.0 1 to 1% tic i 0 ₂ヽ

0-3% C e〇 ₂

0 to 0.0 1% S e,

0-0.05% Co,

0-0.2% Ni 0,

0-0.2% Cr ₂ 0 ₃ By containing, the transmittance of each of ultraviolet light, infrared light, and visible light can be adjusted.

The reasons for limiting each component of the preferred base glass composition will be described in detail below. The following compositions are expressed in mol%.

S i 0 ₂ (silica) is a main component forming the skeleton of glass. 3; 1_Rei ₂ is less than 45% decreases the durability of the glass. If S i 0 ₂ is often to improve the durability, but closely related coefficient of linear expansion to strengthening of the glass is reduced. In order to obtain a sufficient coefficient of linear expansion, Si ₂ is preferably 70% or less, more preferably less than 68%.

B ₂ 0 ₃ is for improvement of durability of glass or a Ingredient which is also used as a dissolution aid. When B ₂ 0 ₃ is more than 5%, the upper limit of 5% since inconvenience during molding due to volatilization or the like is generated.

A 1 ₂ 0 ₃ improves the durability of the glass, also a component contributing to improvement of the closely related Young's modulus strengthening of the glass. But more than 1 5% if becomes low solubility of the glass frame, also the addition of A 1 ₂ 0 ₃ is also effective to lower the coefficient of linear expansion. The preferred range of A 1 ₂ 0 ₃ is 0.5 to 1 5%.

Alkaline earth oxides such as MgO, CaO, Sr0, and Ba◦ are added to improve the durability of glass and to adjust the devitrification temperature, viscosity, expansion rate, and Young's modulus during molding. . If the content of MgO is less than 2.5%, the effect of reducing the devitrification temperature does not appear, and if it exceeds 20%, the devitrification temperature rises conversely, causing production problems.

In the glass of the present invention having both a high Young's modulus and a linear expansion coefficient, C a0 is one of particularly important compositions. If CaO is less than 7.5%, the coefficient of linear expansion and the Young's modulus will be small, and sufficient characteristics will not be obtained. If it exceeds 30%, the devitrification temperature rises, causing production problems.

Since S r 0 and Ba 0 are expensive raw materials, using a large amount thereof increases batch costs. The addition of Sr0 and Ba0 is preferable because it has the effect of reducing the devitrification temperature, but the amount is preferably not more than 10% in terms of cost.

When the sum of these earth elements is 10% or less, glass with a sufficient heat strengthening coefficient If it exceeds 50%, the devitrification temperature rises, causing production problems.

_{_{L i 2 0, Na 2 0}} , an alkali oxide such as K ₂ 0 is Ru promotes the dissolution of the glass. In addition to these, L i ₂ addition of 0 the dissolution accelerating effect is also significantly pull can reduce the effect of the glass transition temperature. This is not preferable because the operating conditions need to be changed in normal float production. Preferably, the amount of Li ₂₀ added does not exceed 10%.

N a ₂ 0 is poor dissolution promotion effect in total less than 1 0% 9% less than or Al force Li oxide amount, N a ₂ 〇 Do exceeds 20%, or total Al force re跫40% If it exceeds, the durability of the glass decreases. Since the K ₂ Ofii often cost Bok increases, K ₂ 〇 is desirably kept to 1 5%.

Υ 0, L a 0, Z r 0 2 improves the Young's modulus of the glass, the effect of improving the durability. In any case, since the raw materials are expensive, the addition of more than 15% raises the cost, and the addition of polyadditive increases the devitrification temperature, which is not preferable.

Iron oxide is present in glass in the form of F e ₂ 0 ₃ and F e 0. In the optical properties of glass, F e ₂ is a component that enhances the ultraviolet ray absorbing ability, and F e 0 is a component that enhances the heat ray absorbing ability.

F e ₂ 0 ₃ total iron oxide in terms of (T-F e ₂ 〇 ₃₎ 0.5 small effect of absorbing ultraviolet and infrared rays is less than 3%, the desired optical characteristics can not be I. On the other hand, the heat-absorbing effect with Τ one F e ₂ C is a too large ferrous oxide, fear not preferable that the temperature of the melting tank ceiling when melted by the radiant heat is more heat-resistant temperature. Furthermore, considering the case of performing continuous production in a glass melting furnace, since it takes T_ F e ₂ 0 ₃ times on the composition changes and is too large, different composition the glass base material, the T_ F e ₂ 0 ₃ of 4 % Or less, and more preferably 2% or less.

T i O 2, C e 0 2 and V ₂ 0 ₅ is Ru coloring component der imparting ultraviolet absorptivity to the glass. N i O, C 00, S e, Mn 0, C r 2 O 3, N d 2 ◦ 3 and E r ₂ 0 ₃ than adding these alone or in combination, mainly adjusts visible light transmittance A desired color tone can be imparted to the ground glass. Preferred combinations for obtaining specific colors An example of the adjustment is shown below.

For example, in the case of a glass with a green color tone whose visible light transmittance (YA) measured using the light source A is as high as 70% or more when the thickness is 4 mm, 0.5 to 2.2% T—F e ₂₀ _In addition to ₃ , it is preferable to use a combination of 0.01 to: L i 0% T i〇 ₂ and 0.05 to 3.0% C e O ₂ .

Another of 3-2% 0. Ding one e ₂ 0 ₃ in order to obtain a green (Grayish green) color gray tinge tinged, 0-0. 2% N I_〇 and / or 0-0. 0 1% S e, 0. 002~0. it is preferably made 05% C O_〇 and 0 to 0.2% of C r ₂ 〇 _third combination. Can be used in combination of the above _{T i 0 2, C e 0} 2 for imparting ultraviolet cut property.

In addition, in order to obtain a gray color with low stimulus purity, 0.3 to ₂ % of T_F e ₂ 〇 ₃ , 0 to 0.2% of Ni〇, 0.002 to 0.05% of C O_〇, 0.000 1-0. it is preferred that a combination 005 percent S e and from 0 to 0.2% of C r ₂ 0 _3. To impart ultraviolet Chikara' preparative can be used in combination of the above _{T i 0 2, C e 0} 2.

The glass composition range of the present invention, in a range of 0 1% S n 0 ₂ in a total amount as a fining agents or reducing agents, but it may also be added to the extent that the present invention does not impair the color tone of interest.

Another preferred base glass composition for tempered sheet glass, expressed as a weight fraction,

60-70% S i 0 ₂ ,

0-5% B ₂ 〇 ₃ ,

1-1 0% eight 1 ₂ 〇 ₃ヽ(However, S I_〇 _2, A 1 ₂ 0 the sum of ₃ is less than 70%) 0-1 5% particularly preferably from 2.2 to 8% of ^ 1 0,

9 6-25% C aO,

0 5% S r 0,

0 5% B a〇,

0 0% of 1 ^ i ₂ 0, 9-2 0% N a ₂ ◦,

0-1 5% 1 _<2 0, (where, L i ₂ 0, Na ₂ 0, K ₂ 〇 amount of sum 1 0% or more 4

◦% or less,)

0 to 15% ₂ 0 ₃ヽ

0-1 5 percent of the 1 ^ a ₂ 0 ₃ヽ

And 0-15% Zr 0 ₂

It is.

This base glass composition containing 9.6% by weight or more of CaO gives a high Young's modulus and a coefficient of linear expansion to the sheet glass.

By setting the MgO content to 2.2% by weight or more in this composition range, it is possible to suppress the unicoloring which is easily observed when a large amount of CaO is contained. MgO below 8% does not cause devitrification of the glass sheet.

A more preferred base glass composition of the tempered glass sheet is 60-70% S i 0 ₂ヽ expressed by weight fraction.

0-5% of 0 ₃ヽ

2. Particularly preferably less than 8% 1. less than 5% eight 1 ₂ 0 _3, (where, S i OA 1 ₂

◦ The sum of ₃ is less than Ί 0%,)

0-15%, particularly preferably 2.2-8% Mg%,

More than 9% and less than 15% C aO,

0-15% S r〇,

0 to 15%: 6 a〇,

0 ~; i 0% i 20,

9-20% Na ₂ 0,

0-1 5% 1 _<2 0, (where, L i ₂ 0, Na ₂ 0, K ₂ 0 content of sum 1 0% to 4 0% or less)

0- 15% 丫₂ 0 ₃ ,

0- 15% of a ₂ 〇 ₃ , And 0-15% Zr 0 ₂

It is.

This 2. glass sheet comprising A 1 ₂ 〇 ₃ of less than 8% by weight, has a high thermal expansion coefficient. 1. A 1 ₂ 0 ₃ of less than 5 wt% gives a higher expansion coefficient glass sheet.

2. MgO content of 2% by weight or more suppresses amber coloring, which is easily seen when a large amount of Ca0 is contained. MgO of less than 8% by weight does not cause devitrification in the sheet glass.

In yet another preferred base glass composition of the reinforcing plate glass, expressed in terms of weight fraction, 60 to 70% 3: 1_Rei _2,

0 to 5% 8 ₂ 0 ₃ヽ

2. Particularly preferably less than 8% 1. less than 5% eight 1 ₂ 0 _3, (where, S i 0 _2, A 1 ₂ ◦ less than the sum of ₃ Ί 0%,)

0 to: I 5% particularly preferably 2.2 to 8% MgO,

5-15% C a〇,

0-15% S r〇,

0-15% of 8 a 0,

0 to: L 0% i 0,

1 3% more particularly preferably more than 25% less than 1 6% N a ₂ 0,

0-1 5% particularly preferably 0.9% less than the K ₂ 0, _{_{(where, L i 2 0, Na 2}} 0,

K ₂ 0 of the sum of 1 to 3% to 40%)

0 to 15% of 丫₂ 〇 ₃ヽ

0 to: I 5% a ₂ 0 ₃ヽ

And 0-15% Zr 0 ₂

It is.

The base glass composition containing 13% by weight of Na ₂₀ gives a high linear expansion coefficient to the sheet glass. Na ₂ O less than 25% by weight degrades the durability of the glass.

Even in this composition range, it can be obtained by limiting the amount of MgO to 2.2 to 8% by weight. The effect is the same. Limiting effect on the A 1 ₂ 0 ₃ amount 1. to less than 5% by weight are also as was mentioned pair first.

1 (the basic glass composition of less than ₂ 〇 weight 0.9% by weight, equal to the impurity levels the amount of K ₂ 0 is included in the generally silica sand or the like. Therefore, kappa ₂ 0 material is not necessary, the material cost of the glass sheet Reduced.

1 Na ₂ 0 less than 6%, does not deteriorate the durability of the glass sheet.

Yet another preferred base glass composition of the tempered glass sheet is 60% or more and less than 63% S i 0 ₂ , expressed by weight fraction,

At least _{_{1% A 1 2 0 3 (}} S i 0 2, A 1 2 0 less than the sum of ₃ 70%)

0 ~ 5%: 6 ₂ 0 ₃ヽ

0 to: L 5% MgO,

5-15% C a 0,

0-15% S r 0,

0 to; 15% of 8a0,

0-20% i 20,

More than 13% and less than 25% N a ₂₀ ,

0 to 15% of ₂₀ ; (However, the sum of Li ₂ 〇, Na ₂₀ and K ₂₀ is 13% or more 4

0% or less,)

0 to 15% of 丫₂ 〇 ₃ ,

0-1 5 percent of the 1 ^ a ₂ 〇 _3,

And 0-15% Zr 0 ₂

It is.

Further preferred base glass composition of the tempered glass sheet,

The base glass composition, expressed as a weight fraction,

63% or more and less than 66% S i〇 ₂ ,

2.less than 8% 1 ₂ 0 ₃ ,

0 5% of 5 ₂ 〇 ₃ , 0-15% of 1 g 0,

5-15% C a0,

0-15% S r 0,

0 to: L 5% 8 a 0,

0 to: L 0% i ₂₀ ,

More than 13% and less than 25% Na ₂₀ ,

0-15% of K ₂ 0, _{_{where, L i 2 0, Na 2}} 0, K 2 0 content of total 13% to 40%)

0-15% of the ¥ ₂ 0 ₃ヽ

0-15% of L a ₂ 0 _3,

And 0-15% Zr 0 ₂

It is.

Further preferred base glass composition of the tempered glass sheet,

The base glass composition, expressed as a weight fraction,

66% -70% S i 0

1 ₂ 〇 _{3 of} less than 2% (however, the sum of S i 〇 ₂ and 8 1 ₂ 0 ₃ is 70% or less)

0-5%: 6 ₂ 〇 ₃ ,

0-15% Mg〇,

5-15% C aO,

0-15% S r 0,

0-15% of 8 aO,

0-10% of 1 ^ i ₂ 〇,

More than 13% and less than 25% Na ₂ ◦,

0-15% of 1 ^ ₂ 0, (where, L i ₂ 0, Na ₂ 0, K ₂ 0 content of total 13% or more 4

0% or less,)

0-15% of the ¥ ₂ 0 ₃ヽ

0 to: L 5% L a ₂ 〇 ₃の And 0-15% Zr 0 ₂

It is.

The glass sheet of this basic glass composition has excellent chemical durability and high thermal strengthening coefficient.

The following is the evaluation of the force on the window glass and how much the glass bends during the operation of the vehicle. Assuming that the car is running at 12 O kmZh / h and the window receiving wind pressure is supported only on the lower side, the displacement of the window glass at each point is approximated by the following equation.

d = 4.38X10 ³ X | Cp | / Et ³

d: strange immin)

E: Young's modulus (GPa)

t: Plate thickness (mm)

Cp: Pressure coefficient (<0)

In the case of window glass on the side of an automobile, a value of -0.3 to -1.0 is generally used for the pressure coefficient Cp. | Cp | in the above equation is the absolute value of the pressure coefficient Cp.

The value of the tensile stress received at each point is determined by the following approximation.

f = 3qx ² / bt ²

f: Tensile stress (MPa)

q: Uniform distribution weight (MPa)

X: Distance from free end (mm)

b: width (= 1)

t: Plate thickness (mm)

From the above formula, the maximum tensile stress value received for each sheet thickness was obtained as shown in Table 1. table 1

Plate thickness (mm) Maximum tensile stress (MPa)

2.1.8.6.6

2.5 58.4

2. 8 3 8. 6

3.1 31.5

3.5 5 24. 7

3.8.2 1

4.8 1 3.1 Therefore, it is currently considered the lower limit of use for veneers.2 At a thickness of 1 mm, if a compressive stress of at least 70 MPa can be applied by strengthening, cracks will develop and lead to fracture. The probability can be kept very low. Therefore, the necessary thermal strengthening coefficient in the present invention was determined to be 35 or more.

The thermal strengthening coefficient is more preferably 35 to 75, particularly preferably 45 to 65. Among the parameters of thermal conductivity, linear expansion coefficient, Young's modulus, and Poisson's ratio determined by the composition of the glass, the ones whose values greatly change depending on the composition are the linear expansion coefficient and the Young's modulus. In order to obtain the above-mentioned thermal strengthening coefficient, the thermal stress coefficient represented by the product of the coefficient of linear expansion and the Young's modulus is preferably 0.70 to 1.20 MPa / ° C.

More preferably, the thermal stress coefficient is between 0.72 and 0.80 MPa / ° C.

To obtain the thermal stress factor, 5 0 ° C; ~ 3 00 average linear expansion coefficient ° C is ^{9 2 X 1 0- 7 ~ 1} 0 5 x 1 O- ^ CT 1 Young's modulus 7 5 9 2 GP a is it is favorable preferred, further, the average linear expansion ^{coefficient, 9 5 X 1 0- 7 °} C- 1 ~ 1 00 X 1 0- 7 ° 1, the Young's modulus 77-8 5 More preferably, it is GPa or more.

The plate glass of the present invention is preferably produced by a float method, but is not necessarily limited to this. Examples 1-2 1

Add ferric oxide, titanium oxide, cerium oxide, cobalt oxide, metallic selenium, nickel oxide, chromium oxide, neodymium oxide, or erbium oxide to the soda-lime-silica glass batch components so that the composition shown in Table 2 is obtained. , A carbon-based reducing agent (specifically, coke powder, etc.) and a fining agent were added and mixed. This raw material was placed in a platinum crucible with a capacity of 250 ml, heated to 1500 ° C in an electric furnace and melted for 4 hours. The melted glass was poured on a stainless steel plate, and gradually cooled to room temperature to obtain a glass plate.

Then, the obtained glass plate is 2.:! Polished to ~ 4.8 mm thick. The polished sheet glass was held in an electric furnace at 700 ° C. for about 3 minutes, then taken out, blown with compressed air at a pressure of 34 MPa, and air-cooled to obtain a tempered glass. From this reinforced glass, a glass の having a length of about 15 mm and 5 mm0 was cut out. The glass plate is heated from room temperature to about 700 ° C at a rate of 5 ° C per minute, and the elongation of the glass is measured using quartz glass as a standard sample to determine the average linear expansion coefficient, glass transition point (Tg), (Td). A 30 x 20 x 6 mm glass block was cut out from the above tempered glass, and the Young's modulus was determined by the sing-around method.

Tables 2 and 3 show the obtained measurement results and the composition of the tempered glass. Table 2, the value of S i 0 ₂ in 3 are rounded up to two decimal places.

As shown in the table, each of the sheet glasses of Examples 1 to 21 has a high thermal strengthening coefficient of 35 or more and a high surface compressive stress value. Each glass has a thermal stress coefficient E of 0.70 to 1.20 MPa / ° C, and has improved toughness. The glass sheets of Examples 1 to 9, 13 to 16 and 18 to 21 all have a preferred range of the base glass composition described in claim 7.

Table 4 shows a comparative example.

Table 4

*:Calculated value

**: Average value of 20-400 ° C

Comparative Example 1 is a commercially available float plate glass composition, which is out of the range of the present invention. The thermal strengthening coefficient of this composition and the surface compressive stress value obtained by air-cooling the composition are shown in the table. It is clear that the reinforcement is inferior to that of the present invention. The Comparative Example 2 N a ₂ 0 is out of range the present invention. On the other hand, Comparative Example 3 is a glass disclosed in Japanese Patent Publication No. 6-53592. In each case, the surface stress value is lower than in the examples of the present invention, and the reinforcing performance is inferior.

As described above in detail, according to the present invention, a tempered glass having a sufficient surface compressive stress value is provided without substantially increasing the capacity of the tempering process.

Claims

The scope of the claims

1. A tempered glass sheet having a thermal strengthening coefficient of 35 to 75, expressed as the quotient obtained by dividing the surface compression stress value (MPa) by the sheet thickness (mm) when the glass sheet is subjected to tempering treatment. A tempered sheet glass characterized by the following.

2. The strengthening sheet glass according to claim 1, wherein the thermal strengthening coefficient is 45 to 65.

3. 50. The thermal stress coefficient represented by the product of the average coefficient of linear expansion and the Young's modulus at C to 350 ° C is 0.70 to 1.2 OMP aZ ° C, according to claim 1 or 2, Glass for tempering.

4. The tempered glass sheet according to any one of claims 1 to 3, wherein the thermal stress coefficient is 0.72 to 0.8 OMP a / ° C.

5. is said average coefficient of linear expansion is ^{^{92 x 1 0- 7 ° C- 1}} ~ 1 05 x 1 0- 7 ° C ', claims, characterized in that Katsuya's modulus is 75 GP a more 5. The tempered glass sheet according to any one of 1 to 4.

6. The average coefficient of linear expansion is ^{^{95 X 1 0- 7 ° C- 1}} ~ 1 00 x 1 0- 7 ° C 1, wherein, wherein Katsuya's modulus is 77 to 85 GP a Item 6. The tempered glass sheet according to any one of Items 1 to 5.

7. The base glass composition, expressed in mole fraction,

45-70% of 310 ₂ヽ

0.5 to 15% of 8 1 ₂ 0 ₃ ,

8 ₂ 0 _{3 of} 0-5%,

2.5-20% MgO,

7. 5-30% 〇 & 0,

0 to 10% S r 0,

0 to 10%: 6 & 0, (However, the sum of the amounts of MgO, Ca0, Sr0, BaO is more than 10% and less than 50%) 0-20% i 20,

9-25% Na ₂ 0,

0-15% of 1 ₂ 0, (where, L i ₂ 〇, Na ₂ 0, K ₂ 0 content of total 10% or more 4

0% or less,)

0 to: 15% { ₂ 0 ₃ }

0-15% L azO

And 0 to 15% of the Z R_〇 ₂

The tempered glass sheet according to any one of claims 1 to 6, comprising:

8. As a coloring component, expressed in mole fraction,

Total iron oxide in terms of 0.3 to 4% of _{_{F e 2 0 3 (T- Fe}} 2 〇 _3),

0.01-1% of Ding i〇 ₂ ,

0-3% of C e 0 _2,

0-0. 01% S e,

0-0.05% 〇00,

0-0.2% Ni 0,

0-0.2% Cr ₂ 0 ₃

The tempered glass sheet according to any one of claims 1 to 7, wherein the glass sheet has a transmittance adjusted to each of ultraviolet light, infrared light, and visible light.

9. The base glass composition, expressed as a weight fraction,

60 丄 70% 3 丄₂ ,

1-10% eight 1 ₂ 0 _3, (wherein, S I_〇 70% less than the sum of ₂ A 1 ₂ 0 ₃ is 60%)

0-5% of the 0 ₃ヽ,

0-15% Mg〇,

9. 6-25% 〇 & 0,

0-15% S r 0,

0 to: L 5% 8 a 0, 0 to 10% L i ₂ 〇,

9-20% of N a ₂ 0,

0-1 5% 1 _<2 0, (where, L i ₂ 0, Na ₂ 0, K ₂ ◦ amount of sum 4 0% inclusive 1 0%)

0 to 15% 丫 2 丫 3,

0 to 15% La ₂ 0 ₃ ,

And 0-15% Zr 0 ₂

Characterized in that it consists of claims 1 to 6 reinforced glazing as claimed in any one of ₍

10. The tempered glass sheet according to claim 9, wherein the MgO content is 2.2 to 8% by weight.

1 1. The base glass composition is expressed as a weight fraction,

60-70% 3 soil ₂ ,

2.8% less than eight 1 ₂ 〇 _3, (where, S i 0 _2, A 1 ₂ 〇 sum of ₃ is less than 70%)

0-5% of; 6 ₂ 0 ₃ヽ

0-15% MgO,

More than 9% and no more than 15% C aO,

0-15% S r 0,

0-15% of 8 a 0,

0 ~ 10%] ^ i 2〇,

9-20% Na ₂ 〇,

0-15% ◦,

_{_{However, L i 2 0, Na 2}} 0, K 2 0 content of sum 10% to 40% or less,

0-1 5 percent of丫2_Rei _3,

0-1 5% a ₂ O s

And 0 to 15% Zr 0 ₂

The tempered glass sheet c according to any one of claims 1 to 6, characterized by comprising:

12. The method according to claim 11, wherein the amount of MgO is 2.2 to 8% by weight. Reinforced glass sheet.

13. The A 1 ₂ 0 ₃ weight reinforcing plate glass according to claim 1 1 or 1 2, characterized in that 1. is less than 5 wt%.

14. The base glass composition, expressed as a weight fraction,

60-70% S i 0 ₂ヽ

2.8% less than eight 1 ₂ 0 _3, (wherein, S I_〇 _2, A 1 ₂ 〇 sum of ₃ is less than 70%)

0-5% of 8 ₂ 〇 ₃ ,

0-15% Mg〇,

5-15% CaO,

0-15% S r 0,

0 to: L 5%; 8 a 0,

0-20% i 20,

More than 13% and less than 25% Na ₂ 〇,

0-1 5% 1 ^ ₂ 0, (where, L i ₂ 0, Na ₂ 0, K ₂ 〇 amount of total 13% or more 4 0% or less)

0-15% of 丫₂ 0 ₃ ,

0 to 15% La ₂ 0 ₃ヽ

And 0 to 15% Zr 0 ₂

Reinforcing reinforced glazing _(15. the MgO amount according to any one of claims 1 to 6 of the mounting serial to claim 14, characterized in that a 2.2 to 8 wt%, characterized in that it consists of For flat glass.

16. The A 1 ₂ 0 ₃ weight reinforcing plate glass according to claim 14 or 1 5, characterized in that 1. is less than 5 wt%.

17. The K ₂ 0 amounts reinforcing plate glass according to any one of claims 14 to 1 6, characterized in that less than 0.9 wt%.

1 8. The N a ₂ 〇 weight reinforcing plate glass according to any one of claims 14 to 17, characterized in that less than 1 6% by weight.

1 9. The base glass composition, expressed as a weight fraction,

60% or more and less than 63% S i〇 ₂ ,

1% or more of eight 1 ₂ 0 ₃ (where, S i 0 _2, A 1 ₂ 0 less than the sum of ₃ 70%)

0-5%: 6 ₂ 0 ₃ヽ

0-15% Mg〇,

5-15% CaO,

0-15% S r 0,

0-15% of 8 a 0,

0 to 10% L i ₂₀ ,

More than 13% and less than 25% Na ₂₀ ,

0 <15% 1 < _{2 2} ,

However, the sum of L i ₂₀ , N a ₂₀ , K ₂ mass is 13% or more and 40% or less,

0 to 15% of 丫₂ 〇 ₃ヽ

0-1 5% a ₂ 0 _3,

And 0-15% Zr 0 ₂

The tempered glass sheet according to any one of claims 1 to 6, characterized by comprising:

20. The base glass composition, expressed as a weight fraction,

63% or more and less than 66% S i 0 ₂ ,

2. Less than 8% 1 ₂ 〇 ₃ ,

0-5% of 8 ₂ 〇 ₃ ,

0 ~; 15% Mg〇,

5 ~: 15% CaO,

0-15% S r 0,

0-15% B aO,

0 to 10% L i ₂ 〇,

More than 13% and less than 25% Na ₂ 〇,

0-1 5% K ₂ 0, _{_{where, L i 2 0, Na 2}} 0, K 2 〇 amount of sum 1 3% or more 40% Less than, )

0-1 5 percent of ¥ ₂ 0 _3,

0 to 15% of a ₂ 〇 ₃ ,

And 0-15% Zr 0 ₂

The tempered glass sheet according to any one of claims 1 to 6, wherein

2 1. The base glass composition is expressed as a weight fraction,

66% to 70% S i 0 ₂ヽ

1 ₂ 0 _{3 of} less than 2% (however, the sum of S i 0 ₂ and 8 1 ₂ 〇 ₃ is 70% or less)

0 of 5%: 6 ₂ 0 _3,

0- 15% MgO,

5-15% CaO,

0-15% S r〇,

0 to; I 5% of 8 a 0,

0 to 10% L i ₂₀ ,

More than 13% and less than 25% Na ₂₀ ,

0% or less,)

0 ~ 15% of 丫₂ 〇 ₃ ,

0 to 15% of a ₂ 〇 ₃ ,

And 0-15% Zr 0 ₂

The sheet glass for tempering _c 22 according to any one of claims 1 to 6, characterized in that it has been subjected to a wind-cooling tempering treatment. 6. The tempered glass sheet as described in the above item.