초록

The present invention can provide an alkali free glass containing as a refining agent, a tin oxide and at least one selected from the group consisting of a cerium oxide, a manganese oxide, a tungsten oxide, a tantalum oxide and a niobium oxide.

대표청구항 ▼

1. An alkali-free glass comprising: (A) a composition including: 50 to 70 wt % of SiO2; 7.5 to 20 wt % of Al2O3; 10 to 15 wt % of B2O3; 0 to 5 wt % of ZnO; and 5 to 30 wt % of at least one of MgO, CaO, SrO and Bao, in which an amount of MgO is 0 to 8 wt %, an amount of CaO is 0 to 10 wt %,

1. An alkali-free glass comprising: (A) a composition including: 50 to 70 wt % of SiO2; 7.5 to 20 wt % of Al2O3; 10 to 15 wt % of B2O3; 0 to 5 wt % of ZnO; and 5 to 30 wt % of at least one of MgO, CaO, SrO and Bao, in which an amount of MgO is 0 to 8 wt %, an amount of CaO is 0 to 10 wt %, an amount of SrO is 0 to 8 wt % and an amount of BaO is 0 to 15 wt %; wherein the composition shows a temperature for a viscosity at 102dPas being equal to or higher than 1,615 ° C., and the composition does not substantially contain each of ZrO2and an alkali metal oxide; (B) total tin oxide in an amount of 0.1 to 2 wt %, as a refining agent, based on the weight of the composition (A); and (C) at least one of total cerium oxide, total manganese oxide, total tungsten oxide, total tantalum oxide and total niobium oxide in an amount of 0.1 to 1 wt %, as a refining agent, based on the weight of the composition (A). 2. The alkali free glass according to claim 1, which comprises the total tin oxide (B) in an amount of 0.4 to 0.8 wt % based on the weight of the composition (A). 3. The alkali free glass according to claim 1, which comprises the total cerium oxide in an amount of more than 0.5 wt %, based on the weight of the composition (A). 4. A flat display panel comprising a pair of glass substrates opposed to each other and a closed space formed between the pair of glass substrates, wherein at least one of the pair of glass substrates is the alkali free glass according to claim 1. 5. A method for producing an alkali-free glass, comprising the steps of: (i) preparing a glass batch comprising: in terms of an oxide 50 to 70 wt % of SiO2; 7.5 to 20 wt % of Al2O3; 10 to 15 wt % of B2O3; 0 to 5 wt % of ZnO; and 5 to 30 wt % in total of at least one of MgO, CaO, SrO and BaO, in which an amount of MgO is 0 to 8 wt %, an amount of CaO is 0 to 10 wt %, an amount of SrO is 0 to 8 wt % and an amount of BaO is 0 to 15 wt %, wherein the glass batch shows a temperature for a viscosity at 102dPas being equal to or higher than 1,615° C., and the glass batch does not substantially contain each of ZrO2and an alkali metal oxide; (ii) melting the glass batch; and (iii) forming the melted batch, wherein SnO2and at least one of CeO2,MnO2,WO3,Ta2O5and Nb2O5are added to the glass batch as a refining agent in amounts of 0.1 to 2 wt % and 0.1 to 1 wt %, respectively, based on the weight of the glass batch. 6. The method for producing an alkali free glass according to claim 5, wherein SnO2in an amount of 0.4 to 0.8 wt % based on the weight of the glass batch is added to the glass batch. 7. The method for producing an alkali free glass according to claim 5, wherein CeO2in an amount of more than 0.5 wt % based on the weight of the glass batch is added to the glass batch. 8. The method for producing an alkali free glass according to claim 5, wherein the forming step iii) is carried out by a down drawing method.