Glass sheet capable of having controlled warping through chemical strengthening

Patent metadata

Field	Value
Publication number	US-10370288-B2
Application number	US-201615565757-A
Country	US
Kind code	B2
Filing date	Apr 25, 2016
Priority date	May 5, 2015
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

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≤SiO 2 ≤78% 5≤Na 2 O≤20% 0≤K 2 O<5% 1≤Al 2 O 3 <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.

First claim

The invention claimed is:

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≤SiO 2 ≤78%;
5≤Na 2 O≤20;
0≤K 2 O<5%;
1≤Al 2 O 3 <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.

2. A float glass sheet according to claim 1 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 1.7% by weight.

3. A float glass sheet according to claim 1 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 0.06% by weight.

4. A float glass sheet according to claim 1 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 0.02% by weight.

5. A float glass sheet according to claim 1 , wherein the composition comprises: 1≤Al 2 O 3 <5 wt %.

6. A float glass sheet according to claim 1 , wherein the composition comprises: 1≤Al 2 O 3 <4 wt %.

7. A float glass sheet according to claim 1 , wherein the composition comprises: 1≤Al 2 O 3 <3 wt %.

8. A float glass sheet according to claim 1 , wherein the composition comprises: 2<Al 2 O 3 <6 wt %.

9. A float glass sheet according to claim 1 , wherein the composition comprises: 2<Al 2 O 3 <4 wt %.

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

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

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

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

14. A float glass sheet according to claim 1 , wherein the glass sheet has:

(

Na
2

⁢
O

)

air

(

Na
2

⁢
O

)

tin

≤
1.

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

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

17. 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.

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

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≤SiO 2 ≤78%;
5≤Na 2 O≤20%;
0≤K 2 O<5%;
1≤Al 2 O 3 <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.

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≤SiO 2 ≤78%;
5≤Na 2 O≤20%;
0≤K 2 O<2%;
1≤Al 2 O 3 <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.

Assignees

• Agc Glass Europe

Inventors

• Lambricht Thomas
• Degand Aline
• Dogimont Audrey
• Scheyvaerts Florence

Classifications

• C03C3/087 Primary

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C4/18

  for ion-sensitive glass · CPC title

• C03C23/008

  comprising a lixiviation step · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title