Glass for chemical strengthening

1. A glass for chemical strengthening comprising, in mole percentage based on following oxides, 55% to 80% of SiO 2 , 3% to 16% of Al 2 O 3 , 0% to 12% of B 2 O 3 , 5% to 16% of Na 2 O, 0% to 4% of K 2 O, 0% to 15% of MgO, 0% to 3% of CaO, 0% to 18% of ΣRO (where R represents Mg, Ca, Sr, Ba or Zn), 0% to 1% of ZrO 2 , 0.005% to 0.5% of SO 3 , and 0.1% to 7% of a coloring component having at least one metal oxide selected from the group consisting of oxides of Co, Mn, Fe, Ni, Cu, Cr, V and Bi.

2. The glass for chemical strengthening according to claim 1 ,

wherein the coloring component in the glass is constituted of, in mole percentage based on oxides, 0.01% to 6% of Fe 2 O 3 , 0% to 6% of Co 3 O 4 , 0% to 6% of NiO, 0% to 6% of MnO, 0% to 6% of Cr 2 O 3 , and 0% to 6% of V 2 O 5 .

3. The glass for chemical strengthening according to claim 1 , comprising 0.005% to 2% of a color correcting component having at least one metal oxide selected from the group consisting of oxides of Ti, Ce, Er, Nd and Se.

4. A glass for chemical strengthening comprising, in mole percentage based on following oxides, 60% to 80% of SiO 2 , 3% to 15% of Al 2 O 3 , 5% to 15% of Na 2 O, 0% to 4% of K 2 O, 0% to 15% of MgO, 0% to 3% of CaO, 0% to 18% of ΣRO (where R represents Mg, Ca, Sr, Ba or Zn), 0% to 1% of ZrO 2 , 1.5% to 6% of Fe 2 O 3 , and 0.1% to 1% of Co 3 O 4 .

5. A glass for chemical strengthening comprising, in mole percentage based on following oxides, 55% to 75% of SiO 2 , 8% to 16% of Al 2 O 3 , 4% to 12% of B 2 O 3 , 7% to 16% of Na 2 O, 0% to 4% of K 2 O, 0% to 3% of MgO, 0% to 3% of CaO, 0% to 5% of ERO (where R represents Mg, Ca, Sr, Ba or Zn), 0% to 1% of ZrO 2 , 1.5% to 6% of Fe 2 O 3 , and 0.1% to 1% of Co 3 O 4 .

6. The glass for chemical strengthening according to claim 1 ,

wherein the coloring component in the glass comprises Co 3 O 4 and Fe 2 O 3 in a mole ratio Co 3 O 4 /Fe 2 O 3 ranging from 0.01 to 0.5.

7. The glass for chemical strengthening according to claim 1 ,

wherein

the coloring component in the glass comprises Co 3 O 4 and Fe 2 O 3 ,

the glass may further comprise 0% to 15% Li 2 O, and

a mole ratio (SiO 2 +Al 2 O 3 +B 2 O 3 )/(ΣR′ 2 O (where R′ represents Na, K or Li)+CaO+SrO+BaO+Fe 2 O 3 +Co 3 O 4 ) is three or more.

8. The glass for chemical strengthening according to claim 1 , comprising 0.005% to 1% of SnO 2 .

9. The glass for chemical strengthening according to claim 1 ,

wherein a minimum value of an absorption coefficient at wavelengths of 380 nm to 780 nm is 1 mm −1 or more.

10. The glass for chemical strengthening according to claim 1 ,

wherein a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass and a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass are both within a range of 0.7 to 1.2.

11. The glass for chemical strengthening according to claim 1 ,

wherein absolute values of variations ΔT (550/600) and ΔT (450/600) calculated from relative values of the absorption coefficients as expressed by the following expressions (1) and (2) are 5% or less:

ΔT(550/600)(%)=[{A(550/600)−B(550/600)}/A(550/600)]×100  (1); and

ΔT(450/600)(%)=[{A(450/600)−B(450/600)}/A(450/600)]×100  (2)

where in the above expression (1), A(550/600) is a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass after 100-hour irradiation with light of a 400 W high-pressure mercury lamp, and B(550/600) is a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass before irradiation with the light; in the above expression (2), A(450/600) is a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass after 100-hour irradiation with light of a 400 W high-pressure mercury lamp, and B(450/600) is a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass before irradiation with the light.

12. The glass for chemical strengthening according to claim 1 ,

wherein when an indentation is formed by using a Vickers indenter in a mirror-finished surface of a glass plate having a thickness of 1 mm made of the glass for chemical strengthening, a load of the Vickers indenter that causes a crack occurrence rate to be 50% is 150 gf or more.

13. A chemical strengthened glass obtained by chemical strengthening a glass for chemical strengthening comprising, in mole percentage based on following oxides, 55% to 80% of SiO 2 , 3% to 16% of Al 2 O 3 0% to 12% of B 7 O 3 , 5% to 16% of Na 2 O, 0% to 4% of K 2 O, 0% to 15% of MgO, 0% to 3% of CaO, 0% to 18% of ΣRO (where R represents Mg, Ca, Sr, Ba or Zn), 0% to 1% of ZrO 2 , and 0.1% to 7% of a coloring component having at least one metal oxide selected from the group consisting of oxides of Co, Mn, Fe, Ni, Cu, Cr, V and Bi,

wherein a depth of a surface compressive stress layer formed in a surface of the chemical strengthened glass by the chemical strengthening is 30 μm or more, and a surface compressive stress of the surface compressive stress layer is 550 MPa or more.

14. The chemical strengthened glass according to claim 13 , wherein said glass for chemical strengthening further comprises 0.005% to 0.5% of SO 3 .

15. The chemical strengthened glass according to claim 13 , wherein said glass for chemical strengthening further comprises 0.005% to 1% of SnO 2 .

16. A glass for chemical strengthening comprising, in mole percentage based on following oxides, 55% to 80% of SiO 2 , 3% to 16% of Al 2 O 3 , 0% to 12% of B 2 O 3 , 5% to 16% of Na 2 O, 0% to 4% of K 2 O, 0% to 15% of MgO, 0% to 3% of CaO, 0% to 18% of ΣRO (where R represents Mg, Ca, Sr, Ba or Zn), 0% to 1% of ZrO 2 , 0.005% to 1% of SnO 2 , and 0.1% to 7% of a coloring component having at least one metal oxide selected from the group consisting of oxides of Co, Mn, Fe, Ni, Cu, Cr, V and Bi.

17. The glass for chemical strengthening according to claim 16 ,

wherein the coloring component in the glass is constituted of, in mole percentage based on oxides, 0.01% to 6% of Fe 2 O 3 , 0% to 6% of Co 3 O 4 , 0% to 6% of NiO, 0% to 6% of MnO, 0% to 6% of Cr 2 O 3 , and 0% to 6% of V 2 O 5 .

18. The glass for chemical strengthening according to claim 16 , comprising 0.005% to 2% of a color correcting component having at least one metal oxide selected from the group consisting of oxides of Ti, Ce, Er, Nd and Se.

19. The glass for chemical strengthening according to claim 16 ,

wherein the coloring component in the glass comprises Co 3 O 4 and Fe 2 O 3 in a mole ratio Co 3 O 4 /Fe 2 O 3 ranging from 0.01 to 0.5.

20. The glass for chemical strengthening according to claim 16 ,

wherein

the coloring component in the glass comprises Co 3 O 4 and Fe 2 O 3 ,

the glass may further comprise 0% to 15% Li 2 O, and

a mole ratio (SiO 2 +Al 2 O 3 +B 2 O 3 )/(ΣR′ 2 O (where R′ represents Na, K or Li)+CaO+SrO+BaO+Fe 2 O 3 +Co 3 O 4 ) is three or more.

21. The glass for chemical strengthening according to claim 16 ,

wherein a minimum value of an absorption coefficient at wavelengths of 380 nm to 780 nm is 1 mm −1 or more.

22. The glass for chemical strengthening according to claim 16 ,

wherein a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass and a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass are both within a range of 0.7 to 1.2.

23. The glass for chemical strengthening according to claim 16 ,

wherein absolute values of variations ΔT (550/600) and ΔT (450/600) calculated from relative values of the absorption coefficients as expressed by the following expressions (1) and (2) are 5% or less:

Δ T (550/600)(%)=[{ A (550/600)− B (550/600)}/ A (550/600)]×100  (1); and

Δ T (450/600)(%)=[{ A (450/600)− B (450/600)}/ A (450/600)]×100  (2)

where in the above expression (1), A(550/600) is a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass after 100-hour irradiation with light of a 400 W high-pressure mercury lamp, and B(550/600) is a relative value of an absorption coefficient at a wavelength of 550 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass before irradiation with the light; in the above expression (2), A(450/600) is a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass after 100-hour irradiation with light of a 400 W high-pressure mercury lamp, and B(450/600) is a relative value of an absorption coefficient at a wavelength of 450 nm to an absorption coefficient at a wavelength of 600 nm, as calculated from a spectral transmittance curve of the glass before irradiation with the light.

24. The glass for chemical strengthening according to claim 16 ,

wherein when an indentation is formed by using a Vickers indenter in a mirror-finished surface of a glass plate having a thickness of 1 mm made of the glass for chemical strengthening, a load of the Vickers indenter that causes a crack occurrence rate to be 50% is 150 gf or more.