Strengthened glass and compositions therefor

1. A glass laminate structure comprising:

an external glass sheet;

an internal glass sheet; and

wherein one or both of the glass sheets comprises SiO 2 +B 2 O 3 +Al 2 O 3 ≥86.5 mol. %, B 2 O 3 (mol. %)≤Al 2 O 3 (mol. %), and R 2 O—RO—Al 2 O 3 <about 5 mol. %, and wherein one or both of the glass sheets is ion-exchanged to a compressive stress of at least about 300 MPa and a depth of layer of compressive stress of at least about 15 microns with a Knoop Scratch Threshold>about 12 N and a hardness to modulus ratio greater than about 0.112, or a Vickers indentation threshold in a range from about 10 to about 15 Kg.

2. The glass laminate structure of claim 1 , wherein one or both of the glass sheets comprises either one or both of the following: SiO 2 +B 2 O 3 +Al 2 O 3 ≥about 88 mol. %, and R 2 O—RO—Al 2 O 3 <about 3 mol. %.

3. The glass laminate structure of claim 1 , wherein either the external glass sheet or the internal glass sheet is a chemically strengthened glass sheet and comprises SiO 2 +B 2 O 3 +Al 2 O 3 ≥86.5 mol. %. and R 2 O—RO—Al 2 O 3 <about 5 mol. %, and wherein the other of the external glass sheet or the internal glass sheet comprises a material selected from the group consisting of soda-lime glass and annealed glass.

4. The glass laminate structure of claim 1 , wherein one or both of the glass sheets further comprises:

between about 69-80 mol. % SiO 2 ;

between about 6-12 mol. % Al 2 O 3 ;

between about 2-10 mol. % B 2 O 3 ;

between about 0-5 mol. % ZrO 2 , Li 2 O, MgO, ZnO and P 2 O 5 ;

between about 6-15 mol. % Na 2 O;

between about 0-3 mol. % K 2 O and CaO; and

between about 0-2 mol. % SnO 2 .

5. The glass laminate structure of claim 1 , wherein one or both of the glass sheets further comprises:

between about 72-80 mol. % SiO 2 ;

between about 8-12 mol. % Al 2 O 3 ;

between about 4-10 mol. % B 2 O 3 ;

between about 0-4 mol. % ZrO 2 , MgO, and ZnO;

between about 0-2 mol. % Li 2 O, CaO, and P 2 O 5 ;

between about 7-14 mol. % Na 2 O;

between about 0.1-2.5 mol. % K 2 O; and

between about 0.1-1.5 mol. % SnO 2 .

6. The glass laminate structure of claim 1 , wherein one or both of the glass sheets further comprises:

between about 74-80 mol. % SiO 2 ;

between about 8-11 mol. % Al 2 O 3 ;

between about 4-9 mol. % B 2 O 3 ;

between about 0-2 mol. % ZrO 2 ;

between about 0-3 mol. % MgO and ZnO;

between about 0-1 mol. % Li 2 O and P 2 O 5 ;

between about 7-12 mol. % Na 2 O;

between about 0.1-2.2 mol. % K 2 O;

between about 0-1.5 mol. % CaO; and

between about 0.1-0.5 mol. % SnO 2 .

7. The glass laminate structure of claim 1 , wherein (R 2 O+RO)/(P 2 O 5 +B 2 O 3 +Al 2 O 3 ) is between about 0.5-1.2, between about 0.6-0.9, or between about 0.65-0.85.

8. The glass laminate structure of claim 1 wherein one or both of the glass sheets is ion-exchanged to a compressive stress of at least about 300 MPa and a depth of layer of compressive stress of at least about 15 microns with a Knoop Scratch Threshold >about 16 N and a hardness to modulus ratio>about 0.116.

9. The glass laminate structure of claim 1 , wherein the internal glass sheet has a thickness ranging from about 0.3 mm to about 1.5 mm, and wherein the external glass sheet has a thickness ranging from about 1.5 mm to about 3.0 mm.

10. The glass laminate structure of claim 1 , wherein the external glass sheet has a thickness ranging from about 0.3 mm to about 1.5 mm, and wherein the internal glass sheet has a thickness ranging from about 1.5 mm to about 3.0 mm.

11. The glass laminate structure of claim 1 , further comprising a polymer interlayer between the external and internal glass sheets, wherein the polymer interlayer comprises a single polymer sheet, a multilayer polymer sheet, or a composite polymer sheet.

12. The glass laminate structure of claim 1 , wherein the structure is selected from the group consisting of an automotive side-window, automotive sunroof, automotive windshield, architectural window, and a display.

13. A glass sheet comprising SiO 2 +B 2 O 3 +Al 2 O 3 ≥86.5 mol. %, B 2 O 3 (mol. %)≤Al 2 O 3 (mol. %), and R 2 O—RO—Al 2 O 3 <about 5 mol. %, wherein the glass sheet, when ion-exchanged to a compressive stress of at least about 300 MPa and a depth of layer of compressive stress of at least about 15 microns, has a Knoop Scratch Threshold >about 12 N and a hardness to modulus ratio greater than about 0.112, or a Vickers indentation threshold in a range from about 10 to about 15 Kg.

14. The glass sheet of claim 13 , further comprising either one or both SiO 2 +B 2 O 3 +Al 2 O 3 ≥about 88 mol. %, and R 2 O—RO—Al 2 O 3 <about 3 mol. %.

15. The glass sheet of claim 13 further comprising:

between about 69-80 mol. % SiO 2 ;

between about 6-12 mol. % Al 2 O 3 ;

between about 2-10 mol. % B 2 O 3 ;

between about 0-5 mol. % ZrO 2 , Li 2 O, MgO, ZnO and P 2 O 5 ;

between about 6-15 mol. % Na 2 O;

between about 0-3 mol. % K 2 O and CaO; and

between about 0-2 mol. % SnO 2 .

16. The glass sheet of claim 13 further comprising:

between about 72-80 mol. % SiO 2 ;

between about 8-12 mol. % Al 2 O 3 ;

between about 4-10 mol. % B 2 O 3 ;

between about 0-4 mol. % ZrO 2 , MgO, and ZnO;

between about 0-2 mol. % Li 2 O, CaO, and P 2 O 5 ;

between about 7-14 mol. % Na 2 O;

between about 0.1-2.5 mol. % K 2 O; and

between about 0.1-1.5 mol. % SnO 2 .

17. The glass sheet of claim 13 further comprising:

between about 74-80 mol. % SiO 2 ;

between about 8-11 mol. % Al 2 O 3 ;

between about 4-9 mol. % B 2 O 3 ;

between about 0-2 mol. % ZrO 2 ;

between about 0-3 mol. % MgO and ZnO;

between about 0-1 mol. % Li 2 O and P 2 O 5 ;

between about 7-12 mol. % Na 2 O;

between about 0.1-2.2 mol. % K 2 O;

between about 0-1.5 mol. % CaO; and

between about 0.1-0.5 mol. % SnO 2 .

18. The glass sheet of claim 13 , wherein (R 2 O+RO)/(P 2 O 5 +B 2 O 3 +Al 2 O 3 ) is between about 0.5-1.2, between about 0.6-0.9, or between about 0.65-0.85.