# US 10,370,288 B2 · Glass sheet capable of having controlled warping through chemical strengthening

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- Number: US 10,370,288 B2
- Document ID: US10370288B2
- Status: Granted
- Kind: B2
- Application number: 15/565,757
- Filed: 2016-04-25
- Published: 2018-05-03
- Granted: 2019-08-06
- Earliest claimed: 2015-05-05
- Assignees: Agc Glass Europe
- Applicants: Agc Glass Europe
- Inventors: Thomas Lambricht; Aline Degand; Audrey Dogimont; Florence Scheyvaerts
- Web page: https://patentgrep.com/patent/US10370288B2

## CPC

- C03C 3/087: containing calcium oxide, e.g. common sheet or container glass
- C03C 3/085: containing an oxide of a divalent metal
- C03C 4/18: for ion-sensitive glass
- C03C 21/002: {to perform ion-exchange between alkali ions (C03C21/005 takes precedence)}
- C03C 23/008: {comprising a lixiviation step}
- C03C 2204/00: Glasses, glazes or enamels with special properties
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

The invention relates to a float glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass: 65≤SiO2≤78% 5≤Na2O≤20% 0≤K2O<5% 1≤Al2O3<6% 0≤CaO<4.5% 4≤MgO≤12% a (MgO/(MgO+CaO)) ratio≥0.5 characterized in that the glass sheet has: (I). The invention corresponds to an easy chemically-temperable soda-silica type glass composition, which is more suited for mass production than aluminosilicate glass, and therefore is available at low cost, and with a base glass/matrix composition that is close to or very similar to compositions already used in existing mass production, and finally which shows reduced or controlled increased warping effect.

## Claims

### Claim 1

A float glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass:
65≤SiO2 ≤78%;
5≤Na2O≤20;
0≤K2O<5%;
1≤Al2O3 <6%;
0≤CaO<4.5%;
4≤MgO≤12%,and
having a (MgO/(MgO+CaO)) ratio≥0.5
wherein the glass sheet has:
0.01
<

(
Na
2
⁢
O
)
air
(
Na
2
⁢
O
)
tin
-
1.03

≤
3.

### Claim 2 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises total iron (expressed in the form of Fe2O3) in a content ranging from 0.002 to 1.7% by weight.

### Claim 3 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises total iron (expressed in the form of Fe2O3) in a content ranging from 0.002 to 0.06% by weight.

### Claim 4 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises total iron (expressed in the form of Fe2O3) in a content ranging from 0.002 to 0.02% by weight.

### Claim 5 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 1≤Al2O3<5 wt %.

### Claim 6 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 1≤Al2O3<4 wt %.

### Claim 7 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 1≤Al2O3<3 wt %.

### Claim 8 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 2<Al2O3<6 wt %.

### Claim 9 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 2<Al2O3<4 wt %.

### Claim 10 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 1.0≤CaO<4.5% wt %.

### Claim 11 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 0.5≤[MgO/(MgO+CaO)]<1.

### Claim 12 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 0.75≤[MgO/(MgO+CaO)]<1.

### Claim 13 (depends on 1)

A float glass sheet according to claim 1, wherein the composition comprises: 0.88≤[MgO/(MgO+CaO)]<1.

### Claim 14 (depends on 1)

A float glass sheet according to claim 1, wherein the glass sheet has:
(
Na
2
⁢
O
)
air
(
Na
2
⁢
O
)
tin
≤
1.

### Claim 15 (depends on 1)

A float glass sheet according to claim 1, wherein the glass sheet has a thickness of 0.8 mm or less.

### Claim 16 (depends on 1)

A float glass sheet according to claim 1, wherein the glass sheet is chemically tempered.

### Claim 17 (depends on 1)

A float glass sheet according to claim 1, wherein the float glass sheet has been chemically tempered and has a surface compressive stress of at least 600 MPa and Depth of exchanged layer of at least 15 μm.

### Claim 18 (depends on 1)

An electronic device, comprising the float glass sheet of claim 1.

### Claim 19

A float glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass:
65≤SiO2≤78%;
5≤Na2O≤20%;
0≤K2O<5%;
1≤Al2O3<6%;
0.6≤CaO<4.5%;
4≤MgO≤12%, and
having a (MgO/(MgO+CaO)) ratio≥0.5,
wherein the glass sheet has:
0.01
<

(
Na
2
⁢
O
)
air
(
Na
2
⁢
O
)
tin
-
1.03

≤
3.

### Claim 20

A float glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass:
65≤SiO2≤78%;
5≤Na2O≤20%;
0≤K2O<2%;
1≤Al2O3<6%;
0≤CaO<2%;
4≤MgO≤12%; and
having 0.75≤(MgO/(MgO+CaO))≤1,
wherein the glass sheet has:
0.01
<

(
Na
2
⁢
O
)
air
(
Na
2
⁢
O
)
tin
-
1.03

≤
3.