Leadless silicate glass composition and pipe cone glass for cathode ray tube

The present invention provides a leadless silicate glass composition with improved X-ray absorptivity and leadless funnel neck glass for cathode ray tube. Its composition contains: (by mass percentage) 42-55% of SiO2, 1-8% of Na2O, 2-10% of K2O, 4-17% of (Na2O+K2O), 0-3% of MgO, 0-4% of CaO, 1-12% of SrO, 5-18% of BaO, 6-26% of (SrO+BaO), 0.3-4% of Al2O3, 0-3% of ZrO2, 0.3-6% of (Al2O3+ZrO2), 0-3% of ZnO, 0-3% of TiO2, 0-3.5% of (ZnO+TiO2), 8-23% of Bi2O3, 0-4% of WO3, 0-8% of La2O3, 0-3% of TeO2, 0-5% of SnO2, 0-3% of In2O3, 0.5-12% of (La2O3+TeO2+SnO2+In2O3) and 0-0.7% of Sb2O3. Said composition contains no PbO, the x-ray absorption coefficient at 0.6 angstrom wavelength is 65cm(-1) or more than that, and the x-ray absorption coefficient at 0.3 angstrom wavelength is 15cm(-1) or more than that, and the average linear expansion coefficient at 20-380deg.C is 98-105X10 to the power-7K(-1).