Alkali-zinc-silicate glass-ceramics and glasses

Claim 2

An alkali-zinc-silicate glass-ceramic, comprising the following components: ______________________________________ Components % by wt. ______________________________________ SiO.sub.2 52.0 to 63.5 Me(III).sub.2 O.sub.3 8.5 to 13.0 K.sub.2 O 0 to 20.5 Na.sub.2 O 1.5 to 20.0 Li.sub.2 O 0 to 5.0 ZnO 3.6 to 8.0 Me(II)O 2.5 to 6.5 TiO.sub.2 + ZrO.sub.2 0.5 to 6.0 SnO.sub.2 0 to 9.5 P.sub.2 O.sub.5 0 to 4.0 F 0 to 2.0 CeO.sub.2 0 to 3.0 ______________________________________ where a) Me(III) 2 O 3 is formed from 0 to 13% by wt. Al 2 O 3 and 0 to 9.5% by wt. La 2 O 3 ; and b) Me(II)O is formed from 0 to 3.5% by wt. CaO, 0 to 4.5% by wt. BaO and 0 to 5.0% by wt. MgO.

Claim 3

The glass ceramic according to claim 1, comprising the following components, wherein the quantities of the components are, independently of one another, as follows: ______________________________________ Component % by wt. ______________________________________ SiO.sub.2 52.0 to 61.0 Al.sub.2 O.sub.3 8.5 to 11.0 La.sub.2 O.sub.3 0 to 2.0 K.sub.2 O 0 to 15.0 Na.sub.2 O 6.0 to 15.0 Li.sub.2 O 0 to 4.0 ZnO 3.6 to 7.0 CaO 0.5 to 3.5 BaO 1.0 to 4.5 TiO.sub.2 0 to 2.8 ZrO.sub.2 0.5 to 5.0 P.sub.2 O.sub.5 0 to 2.0 ______________________________________

Claim 4

The glass ceramic according to claim 1, further comprising leucite crystals.

Claim 5

The glass ceramic according to claim 3, wherein the leucite crystals have an average size of less than 5 μm.

Claim 6

The glass ceramic according to claim 1, further comprising additive dyes, fluorescent agents, opacifiers, or stabilizers or glasses, ceramics, or glass ceramics beyond those present in the glass ceramic of claim 1.

Claim 7

The glass ceramic according to claim 1, wherein the glass ceramic has a linear thermal expansion coefficient of from 8.0 to 18.7×10 -6 K -1 , measured in the temperature range of from 100° to 400° C.

Claim 8

A process for producing a glass ceramic having the following components: ______________________________________ Components % by wt. ______________________________________ SiO.sub.2 52.0 to 63.5 Me(III).sub.2 O.sub.3 8.5 to 13.0 K.sub.2 O 0 to 20.5 Na.sub.2 O 1.5 to 20.0 Li.sub.2 O 0 to 5.0 ZnO 3.6 to 8.0 Me(II)O 2.5 to 6.5 TiO.sub.2 + ZrO.sub.2 0.5 to 6.0 SnO.sub.2 0 to 9.5 P.sub.2 O.sub.5 0 to 4.0 F 0 to 2.0 CeO.sub.2 0 to 3.0 ______________________________________ where a) Me(III) 2 O 3 is formed from 0 to 13% by wt. Al 2 O 3 and 0 to 9.5% by wt. La 2 O 3 ; and b) Me(II)O is formed from 0 to 3.5% by wt. CaO, 0 to 4.5% by wt. BaO and 0 to 5.0% by wt. MgO; comprising producing a glass having the above composition; and subjecting the glass to a heat treatment at a temperature of from 600° to 900° C. from 30 minutes to 5 hours.

Claim 9

A process for producing a glass ceramic having the following components: ______________________________________ Components % by wt. ______________________________________ SiO.sub.2 52.0 to 63.5 Me(III).sub.2 O.sub.3 8.5 to 13.0 K.sub.2 O 0 to 20.5 Na.sub.2 O 1.5 to 20.0 Li.sub.2 O 0 to 5.0 ZnO 3.6 to 8.0 Me(II)O 2.5 to 6.5 TiO.sub.2 + ZrO.sub.2 0.5 to 6.0 SnO.sub.2 0 to 9.5 P.sub.2 O.sub.5 0 to 4.0 F 0 to 2.0 CeO.sub.2 0 to 3.0 ______________________________________ where a) Me(III) 2 O 3 is formed from 0 to 13% by wt. Al 2 O 3 and 0 to 9.5% by wt. La 2 O 3 ; and b) Me(II)O is formed from 0 to 3.5% by wt. CaO, 0 to 4.5% by wt. BaO and 0 to 5.0% by wt. MgO; comprising producing a glass having the above composition; and subjecting the glass to a heat treatment at a temperature of from 600° to 900° C. from 30 minutes to 5 hours.

Claim 10

The process according to claim 7, wherein prior to the heat treatment, the glass is ground and sieved to give a powder with a grain size of less than 90 μm.

Claim 11

An alkali-zinc-silicate glass, comprising the following components: ______________________________________ Components % by wt. ______________________________________ SiO.sub.2 52.0 to 63.5 Me(III).sub.2 O.sub.3 8.5 to 13.0 K.sub.2 O 0 to 20.5 Na.sub.2 O 1.5 to 20.0 Li.sub.2 O 0 to 5.0 ZnO 3.6 to 8.0 Me(II)O 2.5 to 6.5 TiO.sub.2 + ZrO.sub.2 0.5 to 6.0 SnO.sub.2 0 to 9.5 P.sub.2 O.sub.5 0 to 4.0 F 0 to 2.0 CeO.sub.2 0 to 3.0 ______________________________________ where a) Me (III) 2 O 3 is formed from 0 to 13% by wt. Al 2 O 3 and 0 to 9.5% by wt. La 2 O 3 ; b) Me(II)O is formed from 0 to 3.5% by wt. CaO, 0 to 4.5% by wt. BaO and 0 to 5.0% by wt. MgO; and c) the glass contains no B 2 O 3 .

Claim 12

An alkali-zinc-silicate glass, comprising the following components: ______________________________________ Components % by wt. ______________________________________ SiO.sub.2 52.0 to 63.5 Me(III).sub.2 O.sub.3 8.5 to 13.0 K.sub.2 O 0 to 20.5 Na.sub.2 O 1.5 to 20.0 Li.sub.2 O 0 to 5.0 ZnO 3.6 to 8.0 Me(II)O 2.5 to 6.5 TiO.sub.2 + ZrO.sub.2 0.5 to 6.0 SnO.sub.2 0 to 9.5 P.sub.2 O.sub.5 0 to 4.0 F 0 to 2.0 CeO.sub.2 0 to 3.0 ______________________________________ where a) Me (III) 2 O 3 is formed from 0 to 13% by wt. Al 2 O 3 and 0 to 9.5% by wt. La 2 O 3 ; b) Me(II)O is formed from 0 to 3.5% by wt. CaO, 0 to 4.5% by wt. BaO and 0 to 5.0% by wt. MgO; and c) the glass contains no B 2 O 3 .

Claim 13

A moulded dental product comprising the glass ceramic according to claim 1.

Claim 14

Dental material comprising the glass ceramic of claim 1.

Claim 15

Veneering material for all-ceramic or metallic dental superstructures comprising the glass ceramic of claim 1.

Claim 16

A moulded dental product comprising the glass according to claim 9.

Claim 17

Veneering material for all-ceramic or metallic dental superstructures comprising the glass of claim 9.